THE  CHEMISTRY 

OF 

COOKING  AND  CLEANING 

RICHARDS  and  ELUOll 

i 


THE  LIBRARY 

OF 

THE  UNIVERSITY 

OF  CALIFORNIA 

LOS  ANGELES 


I. 


t^ 


S''^UTHERN  BRmNCM, 

UNIVERSITY  OF  CALIFORNIA, 

LIBRARY, 

vLOS  ANGELES,  CALIF. 


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THE  CHEMISTRY  OF 
COOKING  AND  CLEANING 

A  MANUAL  FOR  HOUSEKEEPERS 


ELLEN  H.  RICHARDS 
S.  MARIA  ELLIOTT 


EIGHTH  PRINTING 


^JS-' 


WHITCOMB  &  BARROWS 
BOSTON  1923 


50605 


First  Edition 

Copyright^  iS8i 

By  Estes  &  Lauriat 


Second  Edition 

Copyright,  i8g^ 

By  Home  Science  Publishing  Cot 


Third  Edition 
Copyright,  igoy 
'y\  •;  ;  'r  :  By  ifi^^xkri;  II J ■R\c«aki>s 


MADB  IN  U.  S.  A. 

TROUAS  TODD   CO.,  FRINTBRS 

BOSTON 


PREFACE. 


IN  this  age  of  applied  science,  every  opportunity 
of  benefiting  the  household  should  be  seized 
upon. 

The  family  is  the  heart  of  the  country's  life,  and 
every  philanthropist  or  social  scientist  must  begin 
at  that  point.  Whatever,  then,  will  enlighten  the 
mind,  and  lighten  the  burden  of  care,  of  every 
housekeeper  will  be  a  boon. 

At  the  present  time,  when  the  electric  light  and 
the  gas  stove  are  familiar  topics,  there  is,  after  all, 
no  branch  of  science  which  might  be  of  more 
benefit  to  the  community,  if  it  were  properly  un- 
derstood, than  Chemistry — the  Chemistry  of  Com- 
mon Life. 

There  is  a  space  yet  unoccupied  for  an  elemen- 
tary work  which  shall  give  to  non-scientific  read- 
ers some  practical  information  as  to  the  chemical 
composition  of  articles  of  daily  use,  and  as  to  their 
action  in  the  various  operations  in  which  they  are 
employed. 

The  public  are  the  more  ready  for  the  applica- 
tion of  this  knowledge  since  Chemistry  is  taught 
in  nearly  all  High  Schools,  and  most  persons  have 
a  dim  idea  of  what  some  part  of  it  means.  To 
gather  up  these  indistinct  notions  into  a  definite 
and  practical  form  is  the  aim  of  this  little  book. 


iv  PREFACE. 

There  is,  lingering  in  the  air,  a  great  awe  of 
chemistry  and  chemical  terms,  an  inheritance 
from  the  age  of  alchemy.  Every  chemist  can  re- 
call instances  by  the  score  in  which  manufacturers 
have  asked  for  recipes  for  making  some  substitute 
for  a  well-known  article,  and  have  expected  the 
most  absurd  results  to  follow  the  simple  mixing 
of  two  substances.  Chemicals  are  supposed  by 
the  multitude  to  be  all-powerful,  and  great  ad- 
vantage is  taken  of  this  credulity  by  unscrupulous 
manufacturers. 

The  number  of  patent  compounds  thrown  upon 
the  market  under  fanciful  and  taking  names  is  a 
witness  to  the  apathy  of  housekeepers.  It  is  time 
that  they  should  bestir  themselves  for  their  own 
protection.  A  little  knowledge  of  the  right  kind 
cannot  hurt  them,  and  it  will  surely  bring  a  large 
return  in  comfort  and  economy. 

These  mysterious  chemicals  are  not  so  many 
or  so  complicated  in  structure  but  that  a  little 
patient  study  will  enable  any  one  to  understand 
the  laws  of  their  action,  so  far  as  they  apply  to  the 
common  operations  of  the  household. 

No  attempt  is  here  made  to  cover  the  whole 
ground  of  chemical  science,  but  only  to  explain 
such  of  its  principles  as  are  involved  in  the  raising 
of  bread,  and  in  a  few  other  common  processes. 


PREFACE 

To  THE  Second  Edition. 


THE  science  of  chemistry  has  made  rapid 
strides  in  the  past  fifteen  years.  Biological 
science  has  sprung  from  infancy  to  sturdy  man- 
hood during  the  same  time,  and  a  knowledge  of 
both  with  their  relations  to  each  other  is  necessary 
to  the  right  understanding  of  the  manifold  opera- 
tions of  life.  All  the  sciences  and  all  the  arts  are 
taxed  by  thg  intelligent  home-maker  for  the 
proper  foundation  and  continuance  of  the  complex 
life  of  the  home. 

The  establishment  of  more  homes  and  their 
right  conduct  when  established,  which  results  in 
the  better  utilization  of  time,  money  and  strength, 
means  the  perpetuity,  prosperity  and  power  of  the 
nation. 

Without  trespassing  upon  the  domain  of  house- 
hold bacteriology,  a  knowledge  of  the  chemistry 
of  cooking  and  cleaning  must  include  some  dis- 
cussion of  the  sources  of  dirt,  its  composition  and 
its  dangers,  and  the  discussion  of  methods  for  its 
removal,  which  shall  at  the  same  time  be  speedy, 
safe  and  effectual. 


▼i  PREFACE. 

Experience  teaches  that  in  domestic  work  there 
is  no  best  rule  of  universal  application.  Circum- 
stances vary  so  widely  that  principles,  alone,  can 
be  laid  down.  Each  case  requires  a  large  propor- 
tion of  judgment — a  compound  of  more  complex 
composition  than  any  chemical  substance  ever 
dealt  with. 

If  any  housekeeper  finds  a  method  better  for 
her  purpose  than  the  one  specified  here,  let  her 
keep  to  its  use  and  tell  it  to  others.  This  work 
will  have  accomplished  its  purpose  if  it  interests 
those  who  understand  already  the  principles  of 
cooking  and  cleaning;  gives  a  few  answers  to 
those  who  continually  ask  "Why?"  and  "How?" 
and  stimulates  to  study  and  thought  the  many 
who  have  long  labored  with  willing  hearts  but 
with  untrained  minds  and  hands. 

Boston,  1897. 


CONTENTS. 


PAGB 

Preface  to  First  Edition iii 

Preface  to  Second  Edition t 

PART  I. 

Introduction I 

I.  Matter  and  Its  Composition         ...  5 

II.  Elementary  Chemistry 12 

III.  Starches,  Sugars,  Fats,  Their  Preparation 

AS  Food 24 

IV.  Nitrogenous  Constituents     ....  47 

V.  Flavors  and  Condiments.    Diet   ...  56 

PART   II. 

I.  Dust 71 

II.  Dust  Mixtures  (Grease  and  Dust)       .        .  87 

III.  Stains,  Spots,  Tarnish 100 

IV.  Laundry 118 

V.  Chemicals,  and  Their  Use  in  the  House- 

hold           145 

VI.  Antiseptics,  Disinfectants,  Insecticides     .  165 

Books  of  Reference 181 

Index 183 


INTRODUCTION 

To  THE  Revised  Edition  of  1907. 


IN  the  thirty  years  since  this  little  book  was 
written,  the  interpretation  of  many  scientific 
facts  has  been  changed  as  more  facts  have  been 
discovered,  and  also,  in  many  cases,  the  method 
of  expressing  the  well-established  facts  has  been 
changed  to  agree  with  newer  theories. 

Although  at  first  sight  this  seems  discourag- 
ing, it  should  not  prevent  an  attempt  to  under- 
stand some  of  the  fundamental  laws  upon  which 
every-day  life  and  health  depend.  The  author 
has  already  learned  three  different  systems  of 
expressing  the  same  facts  in  chemistry  and 
expects  to  learn  yet  another. 

In  making  this  revision  a  medium  course  has 
been  chosen.  It  is  not  prepared  for  the  scien- 
tific man,  but  its  mission  is  now,  as  it  has  been 
heretofore,  to  the  average  intelligent  housewife. 
She  needs  to  see  that  there  are  reasons  for  things 
in  order  to  lift  the  monotonous  operations  of  the 
kitchen  in  particular,  and  the  household  in  gen- 


Si  THE   CHEMISTRY   OF 

eral,  from  distasteful  drudgery  to  a  plane  of 
intelligent  direction  of  scientific  processes,  the 
results  of  which  may  be  more  or  less  controlled. 

It  is  this  sense  of  control,  of  power  to  pro- 
duce desired  results,  which  gives  an  interest  to 
daily  duties.  Since  the  good  health  and  earning 
capacity  of  the  family  depend  upon  the  house- 
mother's knowledge  of  the  laws  which  govern 
the  daily  making  and  baking  and  cleaning,  surely 
it  will  be  worth  her  while  to  try  to  absorb  the 
spirit  of  modern  scientific  research,  to  observe 
what  goes  on  in  her  pots  and  pans,  to  watch 
her  oven,  and  especially  to  scrutinize  her  dish 
washing. 

Knowledge  of  foods  and  of  chemical  proc- 
esses is  increasing  so  rapidly  that  what  is  written 
is  out  of  date  before  the  ink  is  dry,  but  a  little 
more  or  less  exact  information  is  not  so  im- 
portant as  that  the  spirit  of  inquiry,  of  open- 
mindedness,  shall  pervade  all  departments  of 
household  activity. 

Thirty  years  ago  very  few  grown  women  had 
received  any  training  in  chemistry.  Chemical 
nomenclature  was  worse  than  Greek  to  them 
Today  the  majority  of  young  housewives  have  a 
small  remnant  of  school  chemistry  among  their 
store  of  miscellaneous  knowledge.  It  is  to  be 
feared  that  it  is  rather  vague,  but  chemistry  is 


COOKING  AND   CLEANING.  3 

not  the  bugbear  it  once  was.  The  present  day 
housewife  is  not  afraid  of  chemical  substances. 

The  great  difficulty  in  explaining  chemical 
results  has  been  in  showing  the  law  of  definite 
proportions,  that  fundamental  law,  discovered 
by  Dalton,  in  and  upon  which  the  whole  theory 
has  been  built. 

The  law  of  exchange  of  different  quantities 
having  different  values  not  according  to  quan- 
tity, but  according  to  value,  has  always  been 
difficult  to  express. 

One  reason  for  dwelling  upon  the  law  of  defi- 
nite proportions  is  because  the  idea  is  so  preva- 
lent that  if  the  effect  of  a  teaspoonful  is  good, 
that  of  a  teaspoonful  and  a  half  is  better,  whereas 
the  extra  half  may  be  the  cause  of  failure.  The 
long  experience  of  a  grocery  clerk  gives  his  hand 
nerves  such  a  response  to  weight  that  he  may 
dispense  with  scales  in  putting  up  a  pound  of 
sugar.  In  this  way  the  skilled  cook  tells  the 
proportions  with  the  exactness  of  the  balance, 
but  woe  betide  the  unskilled  housewife  who 
attempts  the  same  trick. 

One  other  fact  in  relation  to  science,  and  chem- 
ical science  in  particular,  must  be  borne  in  mind. 
While  much  is  known,  there  remains  much  more 
still  hidden.  It  is  practical  wisdom  to  use  all 
that  is  known  and  to  accept  results  as  far  as  they 


4  THE   CHEMISTRY   OF 

prove  beneficial,  without  waiting  to  learn  all  the 
reasons  why.  Not  that  the  search  for  reasons 
should  be  abandoned,  but  that  each  bit  of  knowl- 
edge should  be  applied  as  fast  as  gained. 


THE   CHEMISTRY   OF   COOKING 
AND   CLEANING. 


CHAPTER   I. 
Matter  and  Its  Composition. 

WE  give  the  name  matter  to  the  objects  Ma-.te*. 
which  can  be  recognized  by  any  one  of 
our  senses.  There  are  many  kinds  of  matter  and 
many  forms  of  one  kind.  Ice  melts  into  water, 
water  changes  into  steam.  In  our  stoves,  the 
hard,  black  coal  disappears,  leaving  a  soft,  gray 
ash,  that  weighs  much  less  than  the  original  coal. 
Something  has  been  taken  away. 

The  leaf  is  covered  by  wind-blown  soil  and  ^Stw*"^ 
soon  no  leaf  is  there ;  but  the  matter  of  which  it 
was  composed  is  still  somewhere,  for  that  is 
never  lost.  Living  matter  is  in  constant  change 
from  one  form  to  another.  Our  bodies  are  com- 
posed of  matter,  and  to  their  continued  existence, 
as  well  as  to  their  growth,  material  substances 
are  necessary.  Some  changes  come  quickly,  some 
slowly.  Years,  ages  even,  are  sometimes  neces- 
sary to  bring  about  a  result  that  is  visible  to  us. 


6  THE   CHEMISTRY   OF 

A  familiar  substance,  sugar,  for  example,  may 
be  subjected  to  different  changes.  Put  two  table- 
spoonfuls  of  white  sugar  into  a  scant  half  cup  of 
water.  The  sugar  disappears.  The  clear  water 
changes  to  a  syrupy  liquid.  If  the  water  is 
allowed  to  evaporate  slowly,  the  sugar  is  found 
to  remain. 

A  teaspoonful  of  sugar  dropped  upon  the 
warm  stove  changes  in  character.  There  ap- 
pears a  black  mass,  which  is  readily  recognized 
as  charcoal. 

Add  a  solution  of  an  acid  to  a  solution  of  an 
alkali,  and  observe  that  the  acid  substance  and 
the  alkaline  substance  are  no  longer  in  existence 
as  such.  There  is,  instead,  a  neutral  saline  sub- 
stance dissolved  in  water.  The  new  substance 
has  the  properties  of  neither  of  the  others.  The 
acid  and  the  alkali  have  lost  their  identity. 

Dissolve  a  teaspoonful  of  sugar  in  a  cupful  of 
water.  Add  a  very  little  yeast  and  put  the  cup 
in  a  warm  place.  Soon  bubbles  of  gas  rise  and 
break  on  the  surface;  while,  on  distilling  the 
liquid,  a  new  acquaintance  presents  itself  in  the 
form  of  alcohol.  The  first-mentioned  change  in 
the  sugar — the  solution  of  it  in  water — is  a 
physical  change;  for  the  character  of  the  sub- 
stance is  not  permanently  altered.  The  second 
change — the  charring — is  a  chemical  change — 


COOKING  AND    CLEANING.  7 

the  substance  loses  its  individual  character.  The 
third  change  in  the  sugar — its  fermentation — 
which  is  most  important  for  our  present  purpose, 
is  also  a  chemical  change  but  one  caused  by  the 
action  of  life.  When  the  syrup  ferments,  we 
know  that  living  organisms  are  at  work  in  the 
solution,  changing  the  substance  by  their  own 
processes  of  growth.  To  this  class,  then,  we  may 
apply  the  name  biological  change.  Here  belong 
the  changes  in  our  own  bodies  which  enable  them 
to  live  and  grow.  Death  comes  when  these 
"vital"  changes  can  no  longer  proceed  in  a 
normal,  healthy  manner. 

Changes  in  matter,  then,  are  of  two  kinds. 

I.  Physical.  Change  of  form,  without  per- 
manent loss  of  identity.  This  is  brought  about 
by  outside  forces:  heat,  blows,  etc. 

II.  Chemical.  Complete  change  of  character, 
with  or  without  change  of  form.  This  is  brought 
about  by  chemical  agencies,  by  fire  and  electric- 
ity— also  forces  from  without. 

Physical  and  chemical  forces,  working  to- 
gether, allow  biological  results,  caused  by  living 
cells  producing  energy  by  means  of  their  life 
processes. 

Under  these  heads  come  the  numerous  changes 
which  every  housewife  observes  and  which  all 
should  understand,  so  far  as  such  understanding 
is  necessary  for  the  true  economy  of  the  house. 


THE   CHEMISTRY   OF 


Forms  of 

Matter. 


Causes  of 
Change  in 
Matter. 


We  have  seen  that  matter  is  subject  to  two 
kinds  of  change.  Experience  teaches  that  matter 
exists  in  three  different  forms — soUds,  Hquids 
and  gases.  It  teaches,  also,  that  by  the  action  of 
outside  forces  some  soUds  become  Hquids  and 
some  Hquids  become  gases.  The  reverse  proc- 
ess, also,  is  known — gases  change  into  liquids 
and  liquids  into  solids.  The  chemist  or  physicist 
is  able  to  change  matter  from  one  form  into 
another  in  many  more  instances  than  are  ob- 
served in  ordinary  experience. 

What  causes  can  be  made  to  bring  about  these 
changes?  Before  an  iron  kettle  or  stove  can  be 
made,  the  metal  from  which  it  is  formed  must 
be  subjected  to  intense  heat,  when  it  will  become 
a  liquid  and  can  be  poured  into  molds  of  any 
desired  shape.  Solid  ice  melts  or  becomes  water 
at  a  low  temperature;  but  at  a  higher  degree  of 
temperature,  the  water  becomes  steam  or  gas. 
Some  solids,  as  camphor  and  iodine,  sublime,  that 
is,  pass  directly  into  the  gaseous  form. 

Heat,  then,  is  one  influence  which  brings  about 
a  change  of  state  in  material  substances.  If  heat 
be  abstracted  from  a  liquid,  the  latter  may  be- 
come a  solid,  as  when  water  becomes  ice.  Like 
changes  are  less  readily  brought  about  by  pres- 
sure, gases  becoming  liquids ;  liquids  becoming 
solids.     Cold  and  pressure,  acting  together,  are 


COOKING  AND    CLEANING.  9 

able  to  liquefy  the  air,   and  other  gases  once 
called  permanent. 

Different  degrees  of  heat  produce  varying  Expansion, 
degrees  of  liquefaction.  Sometimes  only  a  semi- 
liquid  state  results,  as  in  the  melting  of  solder, 
of  gelatine  and  of  tar.  Almost  all  matter  (ex- 
cept water  between  32°  and  39°  Fahrenheit) 
expands  or  occupies  more  space  under  the  action 
of  heat ;  but  in  gases  the  proportion  of  expansion 
is  much  the  greatest.  This  expansion  of  gases 
with  heat  makes  possible  the  process  of  ventila- 
tion by  means  of  an  open  fire,  and  is  one  factor 
in  the  rise  of  dough. 

The  solids  may  also  be  changed  to  liquids.  Solution. 
The  degree  of  solubility  of  any  substance  de- 
pends largely  upon  the  temperature  of  the  solv- 
ent. Common  salt  dissolves  nearly  as  well  in 
cold  as  in  warm  water.  "Soda"  and  alum  dis- 
solve more  readily  in  warm  than  in  cold,  while 
cream  of  tartar  requires  hot  water  for  its  com- 
plete solution. 

The  amount  of  solid  which  water  will  dissolve  Saturation, 
usually  increases  with  the  temperature  to  a  cer- 
tain degree.  After  this  no  more  will  dissolve 
and  the  solution  is  "saturated."  Gases  readily 
dissolve  in  water,  but  usually  in  cold  solutions 
only. 

The  action  of  the  liquid  is  more  rapid  if  the 


10 


THE   CHEMISTRY  OF 


Solvents. 


solid  be  first  powdered,  for  a  greater  area  is  thus 
presented  to  the  action  of  the  liquid.  It  is  also 
usually  more  rapid  when  the  substance  is  placed 
upon  or  near  the  surface.  Under  these  condi- 
tions each  particle,  while  dissolving,  is  sur- 
rounded by  a  thin  envelop  of  syrup,  which  be- 
comes heavier  and  sweeter.  The  film  of  syrup 
sinks  into  the  solvent  liquid,  so  that  a  clean  sur- 
face is  continually  exposed  to  be  acted  upon. 
Solution  is  a  valuable  agent  in  bringing  about 
chemical  action  during  many  processes  of  cook- 
ing and  cleaning. 

Water  is  a  nearly  universal  solvent.  It  dis- 
solves larger  quantities  of  more  substances  than 
any  other  liquid.  Some  solids,  however,  dissolve 
more  readily  in  other  liquids,  as  camphor  in  alco- 
hol. Silver,  copper  and  tin  are  not  perceptibly 
dissolved  in  pure  water,  while  most  of  their  com- 
pounds, as  nitrate  of  silver  and  sulphate  of  cop- 
per, are  thus  soluble.  Lead  dissolves  more  read- 
ily in  pure  water  than  in  that  containing  some 
impurities.  Gold  may  be  dissolved  in  a  warm 
mixture  of  two  strong  acids.  Many  of  these 
metallic  solutions  which  may  be  formed  in  cook- 
ing utensils  and  water  pipes  are  poisonous,  and 
a  knowledge  of  them  becomes  a  matter  of  great 
importance  to  all  housekeepers. 

A  process  of  daily  occurrence  in  the  household 


COOKING  AND   CLEANING.  11 

greatly  resembles  solution.  It  consists  in  the 
taking  up  of  water,  which  produces  an  increase 
of  bulk  or  "  swelling,"  but  no  true  solution.  Gel- 
atine swells  in  cold  water  and  may  then  be  dis- 
solved in  hot  water.  Starch  "jells"  by  taking 
up  water;  so  we  soak  the  cereals  which  consist 
largely  of  starch,  that  they  may  be  more  quickly 
acted  upon  by  heat, 


M' 


CHAPTER   II. 
Elementary  Chemistry. 

OST  substances  with  which  we  deal  in  or- 
dinary Hfe  are  compounds  of  two  or  more 
elementary  constituents.  The  grain  of  wheat, 
the  flesh  of  animals,  the  dangerous  poison,  are 
each  capable  of  separation  into  simpler  sub- 
stances. Finally  a  substance  is  found  which  can- 
not be  further  separated.  A  chemical  element 
is  a  substance  which  cannot  be  decomposed  into 
other  substances. 
Elements.  Purc  gold  is  an  element  from  which  nothing 

can  be  taken  different  from  itself,  but  gold  coin 
contains  a  little  copper  or  silver  or  both.  The 
oxygen  of  the  air  is  an  element.  Air  is  a  mix- 
ture of  two  or  more  elements.  Oxygen  and 
hydrogen,  both  gaseous  elements,  unite  in  cer- 
tain proportions  to  form  the  chemical  compound, 
water. 

There  are  about  eighty  of  these  elements 
known  to  the  chemist,  while  their  compounds 
are  infinite.  For  his  convenience  the  chemist 
abbreviates  the  names  of  the  elements  into  sym- 


COOKING  AND    CLEANING.  13 

bols,  which  he  uses  instead  of  the  names.  Usu- 
ally, the  first  or  the  first  two  letters  of  the  Latin 
name  are  taken.  These  symbols  mean  much 
more,  however,  than  time  saved,  as  we  shall  see. 

Most  of  the  elements  unite  with  each  other.  Compounds. 
Then  in  the  resulting  compounds,  one  or  more 
elements  may  be  exchanged  for  others,  so  that  a 
multitude  of  combinations  are  formed  out  of  few 
elementary  substances.  The  bulk  of  our  food, 
clothing  and  furniture  is  made  up  of  only  five  or 
six  of  these  elements,  although  about  twenty  of 
them  enter  into  the  compounds  used  in  the 
household.  The  others  are  found  in  nature,  in 
the  chemical  laboratory  or  in  the  physician's 
medicine  case.  A  few  are  so  rare  as  to  be  con- 
sidered curiosities. 

Every  housewife  should  understand  something  chemical  Laws, 
of  these  chemical  substances — their  common 
forms,  their  nature  and  their  reactions,  that  she 
may  not  be  cheated  out  of  time  and  money,  and, 
more  important  still,  that  she  may  preserve  the 
health  of  those  for  whom  she  cares. 

All  chemical  changes  are  governed  by  laws. 
Under  like  conditions,  like  results  follow.  No 
chemical  sleight  of  hand  can  make  one  pound  of 
washing  soda  do  the  work  of  two  pounds,  or  one 
pound  of  flour  make  a  third  more  bread  at  one 
time  than  at  another. 


14  THE   CHEMISTRY  OF 

^^orti^lf"''^  One  of  the  most  important  of  these  laws  is 
that  known  as  the  Law  of  Definite  Proportions, 
which  states  that  the  various  elements  do  not 
unite  to  form  chemical  compounds  in  any  pro- 
portions whatever,  but  only  in  perfectly  definite 
proportions.  From  this  it  follows  that  to  the 
elements  can  be  assigned  values  which  represent 
the  quantities  of  them  which  enter  into  combina- 
tion with  each  other.  These  values  are  called 
the  combining  weights  or  atomic  weights  of  the 
elements,  the  latter  term  having  been  introduced 
since  it  is  assumed  that  the  elements  are  built  up 
of  extremely  small  particles  of  matter  called 
atoms,  and  that  compounds  are  made  of  groups 
of  these  atoms  called  molecules,  and  since  under 
this  assumption  the  relative  weights  of  the  ele- 
ments which  unite  represent  the  relative  weights 
of  the  atoms  or  multiples  of  them.  Thus,  in  the 
compound  water,  hydrogen  and  oxygen  are 
present  always  in  perfectly  definite  proportions, 
namely,  in  the  relation  of  one  part  by  weight  of 
hydrogen  to  eight  parts  by  weight  of  oxygen; 
and  in  the  compound  acetylene,  the  elements 
carbon  and  hydrogen  are  always  present  in  the 
proportion  of  one  part  of  hydrogen  to  twelve 
parts  of  carbon.  It  is  customary  to  adopt  as  the 
standard  of  reference  one  part  by  weight  of 
hydrogen  and  to  adopt  as  the  combining  weight 


COOKING  AND    CLEANING.  15 

or  atomic  weight  of  other  elements  that  quantity 
of  them  which  combines  with  one  part  of  hydro- 
gen, or  in  some  cases  with  two  or  more  parts  of 
this  element. 

Upon  this  basis  the  atomic  weight  of  oxygen 
is  sixteen  and  that  of  carbon  twelve  times  the 
atomic  weight  of  hydrogen.  The  symbol  of  an 
element  is  made  to  represent  its  constant  atomic 
weight;  so  that,  while  the  word  oxygen  means 
only  the  collection  of  properties  to  which  is  given 
the  name,  the  symbol  O  indicates  a  definite  quan- 
tity of  oxygen  which  is  sixteen  times  the  weight 
of  hydrogen  represented  by  the  symbol  H. 

While  it  is  always  true  that  the  elements  cOjm-  Law  of  Multiple 
bine  with  each  other  only  in  definite  proportions, 
yet  it  is  often  true  that  they  combine  to  form  two 
or  more  definite  compounds.  Such  combinations 
are  governed  by  the  Law  of  Multiple  Propor- 
tions :  When  elements  form  more  than  one  com- 
pound, they  unite  according  to  some  multiple  of 
their  combining  weights. 

Thus,  sulphur  and  oxygen  form  two  different 
compounds  represented  by  the  symbols  SO2  and 
SO3 — where  the  proportions  of  sulphur  to  oxy- 
gen are  thirty-two  to  thirty-two  for  the  first  and 
thirty-two  to  forty-eight  for  the  second,  the  com- 
bining weight  corresponding  to  the  symbol  S 
being  thirty-two. 


Proportions. 


16  THE   CHEMISTRY   OF 

A  partial  list  of  atomic  weights  is  as  follows; 


Element. 

Symbol. 

At.  weight. 

Element.        Symbol. 

At.  weight. 

Aluminum 

Al 

27.1 

Magnesium 

Mg 

24.36 

Calcium 

Ca 

40.1 

Nitrogen 

N 

14.04 

Carbon 

C 

12.0 

Oxygen 

0 

16.0 

Chlorine 

CI 

35-45 

Phosphate 

P 

31.0 

Copper 

Cu 

63.6 

Potassium 

K 

39-15 

Gold 

Au 

197.2 

Radium 

Ra 

225.0 

Hydrogen 

H 

1.008 

Silicon 

Si 

28.4 

Iodine 

I 

126.97 

Silver 

Ag 

107.93 

Iron 

Fe 

55-9 

Sodium 

Na 

23-05 

Lead 

Pb 

206.9 

Sulphur 

S 

32.06 

Lithium 

Li 

7-03 

Zinc 

Zn 

65-4 

Symbols.  The  symbols,  then,  are  the  chemist's  shorthand 

alphabet,  or  his  sign  language.  The  non-scien- 
tific reader  is  apt  to  look  upon  the  acquisition  of 
this  sign  language  as  the  schoolboy  regards  the 
study  of  Chinese — as  the  work  of  a  lifetime.  He 
would  be  near  the  truth  were  he  to  attempt  to 
remember  the  symbols  of  all  the  complicated 
compounds  known  and  constantly  increasing; 
but  a  study  of  the  properties  and  combinations 
of  the  few  which  make  the  common  substances 
of  daily  use  need  not  frighten  the  most  busy 


COOKING  AND   CLEANING.  17 

housewife,  for  they  can  be  comprehended  in  a 
few  hours  of  thoughtful  reading.  Then  a  Uttle 
practice  will  make  them  as  familiar  as  the  recipe 
of  her  favorite  cake.  "To  master  the  symbolical 
language  of  chemistry,  so  as  to  fully  understand 
what  it  expresses,  is  a  great  step  toward  master- 
ing the  science." 

The  exchanges  and  interchanges  among  the  ReactioM. 
elements  by  which  new  compounds  are  produced 
are  called  chemical  reactions.  The  written  ex- 
pression of  the  reaction  is  called  a  chemical 
equation.  In  all  chemical  equations  there  is  just 
as  much  weight  represented  on  one  side  of  the 
sign  of  equality  (  =  )  as  on  the  other, 

C    +    O2    =    CO2 

12    +    32     =    44 

Carbon.        Oxygen,        Carbon  Dioxide. 

HCl     +     NaOH     =     NaCl     +     H^O 

Hydro-  Sodium  Sodium  Water, 

chlpric  Hydrate.  Chloride, 

Acid.  or  Com- 

mon Salt. 

36.5  +  40       =  58.5  +   18 
76.5  =  76.5 

This  shows  that  the  sum  of  the  weights  of 
the  two  substances  taken  is  equal  to  the  sum  of 
the  weights  of  the  new  substances  formed  as  the 
result  of  the  reaction. 


18  THE   CHEMISTRY   OF 

It  is  this  exactness  in  dealing  with  matter 
which  gives  to  the  study  of  chemistry  its  great 
value  from  an  educational  standpoint.  In  the 
economy  of  nature  nothing  is  lost.  Wood  and 
coal  burn  in  our  stoves.  The  invisible  product 
of  their  combustion,  CO2,  passes  into  the  air,  but 
adds  a  definite  amount  to  the  weight  of  the  air. 
Thus  the  symbol  of  this  product  shows  that 
twelve  pounds  of  coal  (which  when  free  of  ash 
is  nearly  pure  carbon)  in  burning  take  from  the 
air  thirty-two  pounds  of  oxygen  and  give  back 
to  the  air  forty-four  pounds  of  carbon  dioxide. 

Similarly  the  symbol  of  water,  H2O  (atomic 
weights,  H  =  I,  O  =  16),  shows  that  for  every 
eighteen  parts  by  weight  of  'water  produced, 
there  will  be  two  parts  by  weight  of  H  and  six- 
teen parts  by  weight  of  O  required. 

Although  the  phenomena  themselves  are  found 
to  be  unchangeable,  our  explanation  of  them  may 
be  modified  as  our  knowledge  increases. 

Present  theories  penetrate  only  a  little  into  the 
real  essence  of  things,  and  the  investigator  soon 
stumbles  upon  questions  whose  explanation  does 
not  at  present  even  seem  to  be  a  possibility. 

(See  late  text-books  on  chemistry  for  the  dif- 
ference between  ions  and  atoms.) 
Oxidation.  One  of  the  most  important  chemical  changes 

that  takes  place  inside  or  outside  the  animal  body 


COOKING  AND    CLEANING.  19 

is  that  union  of  oxygen  (four-fifths  of  the  air) 
with  carbon  or  hydrogen  which  we  call  oxida- 
tion—  under  the  steam  boiler  and  in  the  stove  it 
is  called  combustion.  It  is  the  chief  source  of 
available  power  or  energy  in  either  case.  (See 
pp.  25,  26.) 

The  same  amount  of  heat  is  evolved  when  a 
given  amount  of  substance  is  oxidized,  whether 
the  combustion  takes  place  slowly  or  rapidly. 

An  appreciation  of  these  fundamental  laws  of  The 
chemical   combination   is   needed  to   realize   the 
significance  of  the  recent  work  on  the  use  of 
food  in  the  human  body  as  demonstrated  in  the 
calorimeter. 

Before  a  study  of  the  chemical  composition  of 
food  materials  and  of  the  chemical  and  physical 
changes  occurring  in  the  processes  of  cooking 
as  a  preparation  for  the  best  utilization  of  these 
food  stuffs  could  be  insisted  upon,  it  was  neces- 
sary to  be  convinced  that  the  utilization  of  the 
chemical  compounds,  such  as  sugar,  starch,  albu- 
min, etc.,  was  the  same  in  effect  within  the  body 
as  without,  in  stove  or  furnace. 

For  the  proof  that  the  law  of  the  conserva- 
tion of  energy  held  in  the  life  processes  going 
on  in  the  human  body,  an  examination  of  the 
food  and  of  the  results  of  its  consumption  was 
imperative. 


20  THE   CHEMISTRY   OF 

For  this  purpose  a  "respiration  calorimeter" 
was  set  up.* 

"This  is  a  metal-walled  chamber  in  which  a 
man  lives,  eats,  drinks,  works  and  sleeps.  Pro- 
vision is  made  for  ventilating  the  chamber  and 
for  regulating  the  temperature  and  moisture  of 
the  air  within  it.  The  volume  of  the  ventilating 
air  current  is  measured  and  samples  for  analysis 
are  taken  before  and  after  it  passes  through  the 
chamber,  thus  obtaining  the  amounts  of  carbon 
dioxide  and  water  in  the  respiratory  products. 
The  food,  drink,  feces  and  urine  are  weighed 
and  analyzed,  and  their  potential  energy  is  deter- 
mined, as  is  the  kinetic  energy  given  off  from  the 
body  in  the  forms  of  heat  and  external  muscular 
work. 

"The  devices  for  measuring  the  heat  or  loss 
of  heat  given  off  from  the  body  include:  (i) 
Arrangements  to  prevent  gain  or  loss  of  heat 
in  the  chamber  either  by  the  passage  of  heat 
through  the  walls  or  the  bringing  in  and  taking 
out  of  heat  in  the  ventilating  air  current;  (2) 
arrangements  by  which  the  heat  given  off  in  the 
chamber,  by  the  body  or  otherwise,  is  carried 
out  by  a  current  of  water.  .  .  .  This  current, 
which  is  conveyed  by  copper  pipes,  comes  into 
the  chamber  at  a  low  temperature,  passes  around 
the  interior,  absorbs  the  heat,  and  goes  out  cor- 
respondingly warmer.  The  quantity  of  the  water 
and  the  rise  of  temperature  show  how  much  heat 
is  carried  out." 

*"  Description  of  a  New  Respiration  Calorimeter  and  Experiments  on 
the  Conservation  of  Energy  in  the  Human  Body,"  by  W.  O.  Atwater,  Ph.D., 
Professor  of  Chemistry,  Wesleyan  University,  and  E.  B.  Rose,  Ph.D.,  Pro- 
fessor of  Physics,  Wesleyan  University. 


COOKING  AND   CLEANING.  21 

By  means  of  such  apparatus  there  may  be  de-  o/luc^^  ^*^"' 
termined  questions  pertaining  to  the  demands  Experiments, 
of  the  body  for  nutriment  under  different  condi- 
tions of  work  and  rest;  the  duties  performed  by 
the  different  nutrients  of  food  in  supplying  the 
needs  of  the  body;  and  finally  the  nutritive 
values  of  food  materials  and  the  amount  and 
proportions  best  adapted  to  the  needs  of  people 
of  different  classes,  with  different  occupations 
and  in  different  conditions  of  life. 

By  experiment  it  has  been  found  that  i  gram 
of  carbohydrates  (starch,  sugar,  etc.)  or  proteids 
(lean  meat,  white  of  egg,  etc.)  gives  on  an  aver- 
age about  4.1  calories,*  and  one  gram  of  fats  9.3 
calories.  Therefore  to  find  the  value  of  a  given 
dish  set  upon  the  family  table  is  simple  when 
the  weights  of  the  ingredients  are  known.  For 
instance,  in  a  curry  stew  with  rice,  three  pounds 
of  medium  fat  beef  will  yield  259  grams  proteid 
and  175  grams  of  fat,  while  ten  ounces  of  rice 
will  yield  22.5  grams  proteid,  i  gram  of  fat  and 
222  grams  of  carbohydrates.  Adding  together 
the  carbohydrate  and  proteid  gives  503.5  grams. 
Multiplying  this  number  by  the  4.1  calories  per 
gram  we  have  2,064  calories;  while  multiplying 
the  176  grams  of  fat  by  9.3  gives  1,636  calories 
for  the  fat,  a  total  of  3,700  calories,  or  as  many 

*  For  definition  of  calories,  see  page  47. 


»a  THE   CHEMISTRY   OF 

as  should  be  supplied  by  a  dinner  for  three 
working  men. 

The  housewife  well  understands  that  she  may 
provide  sufficient  food,  but  that  she  cannot  be 
sure  it  will  be  eaten,  or  assimilated  if  it  is  eaten. 
But  she  must  also  understand  that  power  does 
not  come  from  nothing,  and  that  if  sufficient 
nourishment  is  not  provided,  the  body  cannot 
have  its  full  due. 
Powdfrs  ^"^  ^^  *^^  universal  chemical  operations  in 

the  household  is  the  use  of  cream  of  tartar  and 
baking  soda  or  of  baking  powders.  Advantage 
has  been  taken  of  this  fact  to  put  upon  the 
market  many  substitutes  and  variations  with  the 
natural  result  that  the  housewife  is  confused  and 
uncertain.  The  table  on  page  23  may  be  helpful 
in  clearing  up  some  of  the  mysterious  ways  of 
the  substances  themselves  and  of  their  advocates. 

Thus,  84  parts  of  cooking  soda  unite  with  188 
parts  of  cream  of  tartar — if  both  are  pure — to 
give  44  parts  of  the  gas  COg.  Cream  of  tartar 
is  a  compact  powder,  however,  so  that  a  tea- 
spoonful  will  weigh  more  than  a  teaspoonful  of 
soda,  and  illustrates  the  difference  in  accuracy 
between  weighing  and  measuring.  Because 
cream  of  tartar  is  so  liable  to  cake,  a  starch  is 
added  to  the  mixing  for  baking  powder.  For 
home  preparation  5  to  10  per  cent  will  be  enough. 


COOKING  AND   CLEANING. 


23 


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CHAPTER  III. 


Living  and 
Lifelecs 

Matter. 


Chemical 
Change 
Produces 
Heat. 


Starches,  Sugars,  Fats,  Their  Preparation  for  Food. 

THE  material  world  is  divided  into  living  and 
lifel/ess  matter.  All  living  matter  requires 
food  that  it  may  grow,  repair  waste,  and  reproduce 
itself,  if  the  existence  of  its  kind  is  to  be  continued. 
This  food  must  be  made  from  the  material  elements 
we  have  been  studying.  Food  for  the  human  body 
must,  therefore,  contain  such  elements,  in  com- 
bination, as  are  found  in  the  body  substance,  in 
order  that  new  materials  may  be  formed  from 
them  by  the  processes  of  life. 

Wherever  there  is  life,  there  is  chemical  change, 
and,  as  a  rule,  a  certain  degree  of  heat  is  neces- 
sary, in  order  that  chemical  change  may  occur. 
Vegetation  does  not  begin  in  the  colder  climates 
until  the  air  becomes  warmed  by  the  heat  of  the 
spring.  When  the  cold  of  winter  comes  upon 
the  land,  vegetation  ceases.  If  plant  life  is  to  be 
sustained  during  a  northern  winter,  artificial 
warmth  must  be  supplied.  This  is  done  by  heat 
from  a  furnace  or  stove.  In  chemical  terms,  car- 
bon and  hydrogen  from  coal,  wood,  or  gas  are 
caused  to  unite  with  the  oxygen  of  the  air  to  form 
carbon  dioxide  (carbonic  acid  gas)  and  water,  and 


COOKING    AND    CLEANING.  25 

by  this  union  of  two  elements  with  oxygen,  heat 
is  produced. 

C   +0,  =C    O2 
C    H*  +0*  =C    Oz   +2H.  O 

These  two  chemical  reactions  indicate  the  Combu«tion. 
changes  which  cause  the  production  of  artificial 
heat  generally  used  for  domestic  purposes.  All 
living  matter,  whether  plant  or  animal,  is  found 
by  analysis  to  contain  carbon,  oxygen,  hydrogen, 
and  nitrogen.  Other  elements  are  present  in  small 
and  varying  quantities,  but  "the  great  four"  are 
the  essentials.  The  plant  is  able  to  take  all  its 
food  elements  from  air,  water  and  soil,  and,  in 
its  own  cells,  to  manufacture  those  compounds 
upon  which  it  can  feed ;  while  an  animal  cannot  do 
this,  but  must  accept  for  the  most  part  the  manu- 
factured product  of  the  plant.  Man,  therefore, 
finds  his  food  in  both  vegetable  and  animal  sub- 
stances. 

Since  many  animals  live  in  temperatures  in 
which  plants  would  die,  it  is  evident  that  they  must 
have  some  source  of  heat  in  themselves.  This  is 
found  in  the  union  of  the  oxygen  of  the  air 
breathed,  with  carbonaceous  matter  eaten  as  food, 
and  the  formation  of  carbonic  acid  gas  (carbon 
dioxide),  and  water  (CO2  and  HjO),  just  as 
in  the  case  of  the  combustion  of  the  wood  in  the 
grate.    Only,  instead  of  this  union  taking  place  in 


26 


THE    CHEMISTRY    OF 


one  spot,  and  so  rapidly  as  to  be  accompanied  by 
light,  as  in  the  case  of  the  grate  fire,  it  takes  place 
slowly  and  continuously  in  each  living  cell. 
Nevertheless,  the  chemical  reaction  seems  to  be 
identical. 

The  heat  of  the  human  body  must  be  main- 
tained at  37°  C — the  temperature  necessary  for 
the  best  performance  of  the  normal  functions.  Any 
continued  variation  from  this  degree  of  heat  indi- 
cates disease.  Especially  important  is  it  that  there 
be  no  considerable  lowering  of  this  temperature, 
for  a  fall  of  one  degree  is  dangerous. 

The  first  requirement  of  animal  life  is,  then,  the 
food  which  supplies  the  heat  necessary  for  the 
other  chemical  changes  to  take  place.  The  class 
of  foods  which  will  be  considered  here  as  those 
utilized  for  the  production  of  animal  heat  among 
other  functions,  includes  the  carbon  compounds, 
chiefly  composed  of  carbon,  hydrogen  and  oxygen. 

The  slow  combustion  or  oxidation  of  these  car- 
bonaceous bodies  cannot  take  place  without  an 
abundance  of  oxygen;  hence,  the  diet  of  the  ani- 
mal must  include  fresh  air — a  point  too  often  over- 
looked. The  amount  of  oxygen,  by  weight,  taken 
in  daily,  is  equal  to  the  sum  of  all  the  other  food 
elements.  One-half  of  these  consists  of  some  form 
of  starch  or  sugar — the  so-called  carbohydrates, 


COOKING    AND    CLEANING.  27 

in  which  the  hydrogen  and  oxygen  are  found  in 
the  same  proportions  as  in  water.  (The  fats  w»ll 
be  considered  by  themselves.) 

Starches,  sugars  and  gums  are  among  the  con-  starches, 
stituents  of  plants,  and  are  sometimes  found  in 
animals  in  small  quantities.  Starch  is  found  in 
greater  or  less  abundance  in  all  plants  and  is  laid 
up  in  large  quantities  in  the  seeds  of  many  species. 
Rice  is  nearly  pure  starch,  wheat  and  the  other 
cereals  contain  sixty  to  seventy  per  cent  of  it. 
Some  tubers  contain  it,  as  potatoes,  although  in 
less  quantity,  ten  to  twenty  per  cent.  It  is  formed 
by  means  of  the  living  plant-cell  and  the  sun's 
rays,  from  the  carbon  dioxide  and  water  contained 
in  the  air,  and  it  is  the  end  of  the  plant  life — ^the 
stored  energy  of  the  summer,  prepared  for  the 
early  life  of  the  young  plant  another  year.  An 
allied  substance  is  called  cellulose.  This  oc- 
curs under  numerous  forms,  in  the  shells 
and  skins  of  fruits,  in  their  membraneous 
partitions,  and  in  the  cell  walls.  Starch  in  its  com- 
mon forms  is  insoluble  in  water.  It  dissolves  par- 
tially in  boiling  water,  forming  a  transparent  jelr' 
when  cooled. 

Sugars,  also,  are  a  direct  or  indirect  product  of     sugars. 
plant  life.    Common  sugar,  or  cane-sugar,  occurs 
in  the  juices  of  a  few  grasses,  as  the  sugar-cane; 
of  some  trees;  and  of  some  roots.    Milk-sugar  is 


28  THE    CHEMISTRY    OF 

found  in  the  milk  of  mammalia,  while  g^ape-sugar 
is  a  product  of  the  ripening  processes  in  fruit 

Digestion  is  primarily  synonymous  with  solu- 
tion. All  solid  food  materials  must  become  prac- 
tically soluble  before  they  can  pass  through  tlie 
walls  of  the  digestive  system.  As  a  rule,  non-crys- 
talline bodies  are  not  diffusible,  so  that  starch  and 
like  materials  must  be  transformed  into  soluble, 
crystalline  substances,  before  absorption  can  take 
place.  Cane-sugar,  too,  has  to  undergo  a  chemical 
change  before  it  can  be  absorbed;  but  grape  and 
milk  sugars  are  taken  directly  into  the  circula- 
tion. To  this  fact  is  due  a  part  of  the  great  nu- 
tritive value  of  dried  fruits  as  raisins,  dates  and 
figs,  and  the  value  of  milk-sugar  over  cane-sugar, 
for  children  or  invalids.  Chemically  pure  milk- 
sugar  can  now  be  obtained  at  wholesale  for  about 
35  cents  per  pound.  This  may  be  used  in  certain 
diseases  when  cane-sugar  is  harmful.  The  chemi- 
cal transformations  of  starch  and  sugar  have  been 
very  carefully  and  scientifically  studied  with  refer- 
ence to  brewing  and  wine-making.  Several  of  the 
operations  concerned  necessitate  great  precision  in 
respect  to  temperature  and  length  of  time,  and 
these  operations  bear  a  close  analogy  to  the 
process  of  bread-making  by  means  of  yeast.  The 
general  principles  on  which  the  conversion  of 
starch  into  sugar,  and  sugar  into  alcohol,  are  con- 


COOKING    AND    CLEANING.  29 

ducted  will  therefore  be  stated  as  preliminary  to  a 
discussion  of  starch  and  sugar  as  food. 

There  are  two  distinct  means   known  to  the     starch  Con- 

version. 

chemist,  by  which  this  change  can  be  produced. 
One  is  by  the  use  of  acid  and  heat,  which  changes 
the  starch  into  sugar,  but  can  go  no  farther.  The 
other  is  by  the  use  of  a  class  of  substances  called 
ferments,  some  of  which  have  the  power  of  chang- 
ing the  starch  into  sugar,  and  others  of  changing 
the  sugar  into  alcohol  and  carbon  dioxide.  These 
ferments  are  in  great  variety  and  the  seeds  of 
some  of  them  are  always  present  in  the  air.  Among 
the  chemical  substances  called  ferments,  one  is 
formed  in  sprouting  grain  which  is  called  diastase 
or  starch  converter,  which  first,  under  the  in- 
fluence of  warmth,  changes  the  starch  into  a  sugar, 
as  is  seen  in  the  preparation  of  malt  for  brewing. 
The  starch  (CgHioOs),  first  takes  up  water  (H^O), 
and,  under  the  influence  of  the  ferment,  is  changed 
into  maltose.  Cane-sugar  is  readily  converted 
into  two  sugars,  dextrose  and  levulose,  belonging 
to  the  glucoses. 

Cxt    H„  Oil    +H,  O   4-ferment=2C.    His  O. 

Cane-Sugar.  Water.  Dextrose  and  Levulose. 

Glucose  and  maltose  are  converted  by  yeast  into     sugar 
alcohol  and  carbon  dioxide.    In  beer,  the  alcohol 
is  the  product  desired,  but  in  bread-making  the 


30  THE    CHEMISTRY    OF 

chief  object  of  the  fermentation  is  to  produce  car- 
bon dioxide  to  puff  up  the  bread,  while  the  al- 
cohol escapes  in  the  baking. 

r     2C,    H,  O 
C.    H..  O.  =  J  ^'«'^'''- 

Dextrose.  I        2C      O2 

V  Carbon  Dioxide. 

The  alcohol,  if  burned,  would  give  carbon  dioxide 
and  water, 

2C,    H«  O   +12O    =4C    O2  H-6H2  O 

Alcohol.         Oxygen.         Carbon  Dioxide.     Water. 

It  will  be  seen,  from  the  previous  equations, 
that  nothing  has  been  lost  during  the  process. 
The  six  atoms  of  carbon  in  the  original  starch 
reappear  in  the  carbon  dioxide  at  the  end, 
2C02H-4C02.  Two  atoms  of  hydrogen  from  the 
water,  and  thirteen  atoms  of  oxygen  from  the 
water  and  the  air  have  been  added.  Reckoning 
the  atomic  weights  of  the  starch  used,  the  carbon 
dioxide  and  the  water  formed,  we  find  that,  in 
round  numbers,  sixteen  pounds  of  starch  will  yield 
twenty-six  pounds  of  gas  and  ten  pounds  of  water, 
or  more  than  double  the  weight  of  the  starch. 
These  products  of  decomposition  are  given  back 
to  the  air  in  the  same  form  in  which  those  sub- 
stances existed  from  which  the  starch  was  orig- 
inally formed. 
S'the*'^*'°"  The  same  cycle  of  chemical  changes  goes  on  in 

Tract!''*  the  human    body   when   starchy    substances  are 


COOKING    AND    CLEANING.  31 

taken  as  food.  Such  food,  moistened  and  warmed 
in  the  mouth,  becomes  mixed  with  air  through 
mastication,  by  reason  of  the  property  of  the  sa- 
liva to  form  froth,  and  also  becomes  impregnated 
with  ptyalin,  a  substance  which  can  change  starch 
into  sugar  as  can  the  diastase  of  the  malt.  The 
mass  then  passes  into  the  stomach,  and  the 
change,  once  begun,  goes  on.  As  soon  as  the 
sugar  is  formed,  it  is  absorbed  into  the  circu- 
latory system  and,  by  the  life  processes,  is  oxi- 
dized, i.  e.,  united  with  more  oxygen  and  changed 
finally  into  carbon  dioxide  and  water. 

No  starch  is  utilized  in  the  human  system  as 
starch.  It  must  undergo  transformation  before  it 
can  be  absorbed.  Therefore  starchy  foods  must 
not  be  given  to  children  before  the  secretion  of 
the  starch  converting  ferments  has  begun,  nor  to 
any  one  in  any  disease  where  the  normal  action  of 
the  glands  secreting  these  ferments  is  interrupted. 
Whatever  starch  passes  out  of  the  stomach 
unchanged,  meets  a  very  active  converter  in 
the  intestinal  juice.  If  grains  of  starch  escape 
these  two  agents,  they  leave  the  system  in  the 
same  form  as  that  in  which  they  entered  it. 

Early  man,  probably,  lived  much  like  the  beasts, 
taking  his  food  in  a  raw  state.  Civilized  man  re- 
quires much  of  the  raw  material  to  be  changed,  by 
the  action  of  heat,  into  substances  more  palatable 
and  already  partly  digested. 


82  THE    CHEMISTRY    OF 

The  chemistry  of  cooking  the  raw  materials  is 
very  simple.  It  is  in  the  mixing  of  incongruous 
materials  in  one  dish  or  one  meal  that  complica- 
tion arises. 

Since  fully  one-half  of  our  food  is  made  up  of 
starches  and  sugars,  it  is  pertinent  to  examine, 
beside  their  chemical  composition,  the  changes 
which  they  may  undergo  in  the  processes  of  cook- 
ing that  can  render  them  more  valuable  as  food, 
or  which,  on  the  other  hand,  may  in  large  meas- 
ure destroy  their  food  value. 

The  cooking  of  starch,  as  rice,  farina,  etc.,  re- 
quires littie  explanation.  The  starch  grains  are 
prepared  by  the  plant  to  keep  during  a  season  of 
cold  or  drought  and  are  very  close  and  compact; 
they  need  to  be  swollen  and  distended  by  moisture 
in  order  that  the  chemical  change  may  take  place 
readily,  as  it  is  a  law,  that  the  finer  the  particles, 
the  sooner  a  given  change  takes  place,  as  has 
been  explained  in  a  previous  chapter.  Starch 
grains  may  increase  to  twenty-five  times  their  bulk 
during  the  process  of  hydration. 

The  cooking  of  the  potato  and  other  starch-con- 
taining vegetables,  is  likewise  a  mechanical  proc- 
ess very  necessary  as  a  preparation  for  the  chem- 
ical action  of  digestion;  for  raw  starch  has  been 
shown  to  require  a  far  longer  time  and  more  di- 
gestive power  than  cooked  starch.    Change  takes 


COOKING    AND    CLEANING.  33 

place  slowly,  even  with  thorough  mastication,  un- 
less the  starch  is  heated  and  swollen,  and,  in  case 
the  intestinal  secretion  is  disturbed,  the  starch 
may  not  become  converted  at  all. 

The  most  important  of  all  the  articles  of  diet  Bread, 
which  can  be  classed  under  the  head  of  starchy 
foods  is  bread.  Wheat  bread  is  not  all  starch,  but 
it  contains  a  larger  percentage  of  starch  than  of 
anything  else,  and  it  must  be  discussed  under  this 
topic.  Bread  of  some  kind  has  been  used  by  man- 
kind from  the  first  dawn  of  civilization.  During 
the  earlier  stages,  it  consisted  chiefly  of  powdered 
meal  and  water,  baked  in  the  sun,  or  on  hot 
stones.  This  kind  of  bread  had  the  same  charac- 
teristics as  the  modern  sea-biscuit,  crackers  and 
hoe-cake,  as  far  as  digestibility  was  concerned.  It 
had  great  density,  it  was  difficult  to  masticate, 
and  the  starch  in  it  presented  but  little  more  sur- 
face to  the  digestive  fluids  than  that  in  the  hard 
compact  grain,  the  seed  of  the  plant. 

Experience  must  have  taught  the  semi-civilized 
man  that  a  light  porous  loaf  was  more  digestible 
than  a  dense  one.  Probably  some  dough  was  ac- 
cidentally left  over,  yeast  plants  settled  upon  it 
from  the  air,  fermentation  set  in,  and  the  possibil- 
ity of  porous  bread  was  thus  suggested. 

The  small  loaf,  light,  spongy,  with  a  crispness 
and  sweet,  pleasant  taste,  is  not  only  aesthetically, 


84  THE    CHEMISTRY    OF 

but  chemically,  considered  the  best  form  in  which 
starch  can  be  presented  to  the  digestive  organs. 
The  porous  condition  is  desired  in  order  that  as 
large  a  surface  as  possible  shall  be  presented  to 
the  action  of  the  chemical  converter,  the  pt>'^alin 
of  the  saliva,  and,  later,  to  other  digestive  fer- 
ments. There  is  also  a  better  aeration  in  the  proc- 
ess of  mastication. 

The  ideal  bread  for  daily  use  should  fulfill  cer- 
tain dietetic  conditions : 

1.  It  should  retain  as  much  as  possible  of  the 
nutritive  principles  of  the  grain  from  which  it  is 
made. 

2.  It  should  be  prepared  in  such  a  manner  as  to 
secure  the  complete  assimilation  of  these  nutri- 
tive principles. 

3.  It  should  be  light  and  porous,  so  as  to  allow 
the  digestive  juices  to  penetrate  it  quickly  and 
thoroughly. 

4.  It  should  be  especially  palatable,  so  that  one 
may  be  induced  to  eat  enough  for  nourishment. 

5.  It  should  be  nearly  or  quite  free  from  coarse 
bran,  which  causes  too  rapid  muscular  action  to 
allow  of  complete  digestion.  This  effect  is  also 
produced  when  the  bread  is  sour. 

Ordinary  Graham  bread,  brown  bread  and  the 
black  bread  of  Germany  fulfill  conditions  i  and  4, 
but  fail  in  the  other  three.    Bakers'  bread  of  fine 


COOKING    AND    CLEANING.  35 

white  flour  fulfills  2,  3  and  5,  but  fails  in  the  other 
two.  Home-made  bread  often  fulfills  conditions 
4  and  5,  but  fails  in  the  other  three. 

Very  early  in  the  history  of  the  human  race  y^t?*  *" 
leavened  bread  seems  to  have  been  used.  This  was 
made  by  allowing-  flour  and  water  to  stand  in  a 
warm  place  until  fermentation  had  well  set  in.  A 
portion  of  this  dough  was  used  to  start  the  process 
anew  in  fresh  portions  of  flour  and  water.  This 
kind  of  bread  had  to  be  made  with  great  care,  for 
germs  different  from  yeast  might  get  in,  forming 
lactic  acid — the  acid  of  sour  milk — and  other  sub- 
stances unpleasant  to  the  taste  and  harmful  to  the 
digestion. 

Butyric  acid  occurs  in  rancid  butter  and  in  many 
putrified  organic  substances.  A  sponge  made  from 
perfectly  pure  yeast  and  kept  pure  may  stand  for  a 
long  time  after  it  is  ready  for  the  oven  and  still 
show  no  sign  of  sourness. 

On  account  of  the  disagreeable  taste  of  leaven 
and  because  of  the  possibility  that  the  dough  might 
reach  the  stage  of  putrid  fermentation,  chemists 
and  physicians  sought  for  some  other  means  of 
rendering  the  bread  light  and  porous.  The  search 
began  almost  as  soon  as  chemistry  was  worthy  the 
name  of  a  science,  and  one  of  the  early  patents 
bears  the  date  1837.  Much  time  and  thought  have 
been     devoted     to     the     perfecting     of     unfer- 


86  THE    CHEMISTRY    OF 

mented  bread;  but  since  the  process  of  beer- 
making  has  been  universally  introduced,  yeast  has 
been  readily  obtained,  and  is  an  effectual  means  of 
giving  to  the  bread  a  porous  character  and  a  pleas- 
ant taste.  Since  the  chemistry  of  the  yeast  fer- 
mentation has  been  better  understood,  a  change  of 
opinion  has  come  about,  and  nearly  all  scientific 
and  medical  men  now  recommend  fermented  bread. 
The  bacteriology  of  bread  and  bread-making  is 
yet  somewhat  obscure.  The  ordinary  yeasts  are  so 
mingled  with  bacteria  that  the  part  which  each 
plays  is  not  yet  understood.  Only  experiments 
long  continued  will  solve  these  problems. 
ac*ti ™s''ti  ^^'  The    chemical    reactions    concerned    in  bread- 

i^g.*'^'^^^'^*  raising  are  similar  to  those  in  beer-making.  To 
the  flour  and  warmed  water  is  added  yeast,  a  mi- 
croscopic plant,  capable  of  causing  the  alcoholic 
fermentation.  The  yeast  begins  to  act  at  once,  but 
slowly;  more  rapidly  if  sugar  has  been  added  and 
the  dough  is  a  semi-fluid.  Without  the  addition 
of  sugar  no  change  is  evident  to  the  eye  for  some 
hours,  as  the  fermentation  of  sugar  from  starch,  by 
the  diastase,  gives  rise  to  no  gaseous  products.  As 
soon  as  the  sugar  is  decomposed  by  the  yeast  plant 
into  alcohol  and  carbonic  acid  gas  (carbon  diox- 
ide), the  latter  product  makes  itself  known  by  the 
bubbles  which  appear  and  the  consequent  swelling 
of  the  whole  mass. 


COOKING    AND    CLEANING.  37 

It  is  the  carbon  dioxide  which  causes  the  sponge- 
like condition  of  the  loaf  by  reason  of  the  peculiar 
tenacity  of  the  gluten,  one  of  the  constituents  of 
wheat.  It  is  a  well-known  fact  that  no  other  kind 
of  grain  will  make  so  light  a  bread  as  wheat.  It  is 
the  right  proportion  of  gluten  (a  nitrogenous  sub- 
stance to  be  considered  later)  which  enables  the 
light  loaf  to  be  made  of  wheat  flour. 

The  production  of  carbon  dioxide  is  the  end  of 
the  chemical  process.  The  rest  is  purely  mechanical. 
The  kneading  is  for  the  purpose  of  rendering  the 
dough  elastic  by  the  spreading  out  of  the  already 
fermented  mass  and  its  thorough  incorporation 
with  the  fresh  flour.  Another  reason  for  kneading 
is,  that  the  bubbles  of  gas  may  be  broken  up  into 
as  small  portions  as  possible,  in  order  that  there 
may  be  no  large  holes,  only  very  fine  ones, 
evenly  distributed  through  the  loaf,  when  it  is 
baked. 

The  temperature  at  which  the  dough  should  be 
maintained  during  the  chemical  process  is  an  im- 
portant point.  If  the  characteristics  of  "home- 
made" bread  are  desired,  it  is  found  to  be  better  to 
use  a  small  amount  of  yeast  and  to  keep  the  dough 
at  a  temperature  from  55  degrees  to  60  degrees  for 
twelve  to  fifteen  hours,  than  to  use  a  larger  quantity 
of  yeast  and  to  cause  its  rapid  growth.  The  changes 
which  produce  the  desired  effect  are  not  fully  under- 

50605 


88  THE    CHEMISTRY    OF 

stood.  Above  90  degrees  the  production  of  acetic 
acid — the  acid  of  vinegar — is  Hable  to  occur:  for 
this  temperature,  while  unfavorable  for  the  yeast 
plant,  is  favorable  for  the  growth  of  the  particular 
bacterium  which  produces  acetic  acid. 

C2      He  O     +O2     =€2      H4  O2     +H2  O 
Alcohol.  Acetic  Water. 

Acid. 

After  the  dough  is  stiffened  by  a  little  fresh  flour 
and  is  nearly  ready  for  the  oven,  the  temperature 
may  be  raised,  for  a  few  minutes,  to  100  degrees 
or  165  degrees  F.  The  rapid  change  in  the  yeast  is 
soon  stopped  by  the  heat  of  the  oven. 
BaWn  °*  '^^^  baking  of  the  loaf  has  for  its  object  to  kill 

the  ferment,  to  heat  the  starch  sufficiently  to  render 
it  easily  soluble,  to  expand  the  carbon  dioxide  and 
drive  off  the  alcohol,  to  stiffen  the  gluten,  and  to 
form  a  crust  which  shall  have  a  pleasant  flavor. 
The  oven  must  be  hot  enough  to  raise  the  tempera- 
ture of  the  inside  of  the  loaf  to  212  degrees  F.,  or 
the  bacteria  will  not  all  be  killed.  A  pound 
loaf,  four  inches  by  four  by  nine,  may 
be  baked  three-quarters  of  an  hour  in  an 
oven  where  the  initial  temperature  is  400 
degrees  F.,  or  for  an  hour  and  a  half,  where 
the  temperature  during  the  time  does  not  rise  above 
350  degrees  F.  Quick  baking  gives  a  white  loaf, 
because  the  starch  has  undergone  but  little  change. 


COOKING    AND    CLEANING.  39 

The  long,  slow  baking  gives  a  yellow  tint,  with  the 
desirable  nutty  flavor,  and  crisp  crust.  Different 
flavors  in  bread  are  supposed  to  be  caused  by  the 
different  varieties  of  yeast  used  or  by  bacteria^ 
which  are  present  in  all  doughs,  as  ordinarily 
prepared. 

The  brown  coloration  of  the  crust,  which  gives 
a  peculiar  flavor  to  the  loaf,  is  caused  by  the  forma- 
tion of  substances  analogous  to  dextnne  and  cara- 
mel, due  to  the  high  heat  to  which  the  starch  is 
subjected. 

One  hundred  pounds  of  flour  are  said  to  make 
from  126  to  150  pounds  of  bread.  This  increase  of 
weight  is  due  to  the  incorporation  of  water,  pos- 
sibly by  a  chemical  union,  as  the  water  does  not 
dry  out  of  the  loaf,  as  it  does  out  of  a  sponge.  The 
bread  seems  moist  when  first  taken  from  the  oven, 
and  dry  after  standing  some  hours,  but  the  weight 
will  be  found  nearly  the  same.  It  is  this  probable 
chemical  change  which  makes  the  difference,  to 
delicate  stomachs,  between  fresh  bread  and  stale.  A 
thick  loaf  is  best  when  eaten  after  it  is  twenty-four 
hours  old,  although  it  is  said  to  be  "done"  when 
ten  hours  have  passed.  Thin  biscuits  do  not  show 
the  same  ill  effects  when  eaten  hot.  The  bread 
must  be  well  baked  in  any  case,  in  order  that  the 
process  of  fermentation  may  be  stopped.  If  this  be 
stopped  and  the  mastication  be  thorough,  so  that 


40 


THE    CHEMISTRY    OF 


Expansion  of 
Water  into 
Steam. 


Methods  of 
Obtaining 
Carbon  dioxide. 


the  bread  is  in  finely  divided  portions  instead  of  in 
a  mass  or  ball,  the  digestibility  of  fresh  and  stale 
bread  is  about  the  same. 

The  expansion  of  water  or  ice  into  seventeen 
hundred  times  its  volume  of  steam  is  sometimes 
taken  advantage  of  in  making  snow-bread,  water- 
gems,  etc.  It  plays  a  part  in  the  lightening  of 
pastry  and  crackers.  Air,  at  70  degrees,  doubles 
its  volume  at  a  temperature  of  560°  F.,  so  that  if  air 
is  entangled  in  a  mass  of  dough,  it  gives  a  certain 
lightness  when  the  whole  is  baked.  This  is  the 
cause  of  the  sponginess  of  cakes  made  with  eggs. 
The  viscous  albumen  catches  the  air  and  holds  it, 
even  when  it  is  expanded,  unless  the  oven  is  too 
hot,  when  the  sudden  expansion  is  liable  to  burst 
the  bubbles  and  the  cake  falls. 

As  has  been  said,  the  production  of  the  porous 
condition,  by  means  of  carbon  dioxide,  generated 
in  some  other  way  than  by  the  decomposition  of 
starch,  was  the  study  of  practical  chemists  for  some 
years. 

A  simple  method  for  obtaining  the  carbon  diox- 
ide is  by  heating  bicarbonate  of  sodium. 

2Na  H  C    O3    4-heat  =  Na^  C    Os    4-H2  O    +C    O, 

The  bicarbonate  splits  up  into  sodium  carbonate, 
water,  and  carbon  dioxide.  The  bread  is  light  but 
yellow.     Some  of  the  carbonate  remains  in  the 


COOKING    AND    CLEANING.  41 

bread,  and  as  it  neutralizes  the  add  of  the  gastric 
juice,  digestion  may  be  retarded.  It  also  acts  upon 
the  gluten  producing  an  unpleasant  odor. 

Among  the  first  methods  proposed  was  one  un- 
doubtedly the  best  theoretically,  but  very  difficult 
to  put  in  practice,  viz.,  the  liberation  of  carbon 
dioxide  from  bicarbonate  of  sodium  by  means  of 
muriatic  acid. 

Na  H  C    O3   +H  CI  =Na  CI  +H2  O   +C    O, 

"  Soda."  Hydrochloric     Common  Water.     Carbon  dioxide. 

Acid.  Salt. 

This  liberation  of  gas  is  instantaneous  on  the  con- 
tact of  the  acid  with  the  "soda,"  and  only  a  skilled 
hand  can  mix  the  bread  and  place  it  in  the  oven 
without  the  loss  of  much  of  the  gas.  Tartaric  acid, 
the  acid  phosphates,  sour  milk  (lactic  acid),  vinegar 
(acetic  acid),  alum — all  of  which  have  been  used — 
are  open  to  the  same  objection.  Cream  of  tartar 
is  the  only  acid  substance  commonly  used  which 
does  not  liberate  the  gas  by  simple  contact  when 
cold.  It  unites  with  "soda"  only  when  heated,  be- 
cause it  is  so  slightly  soluble  in  cold  water.  For  the 
even  distribution  of  the  gas  by  thorough  mixing, 
cream  of  tartar  would  seem  to  be  the  best;  but  as, 
beside  gas,  there  are  other  products  which  remain 
behind  in  the  bread  in  the  case  of  all  the  so-called 
baking  powders,  the  healthfulness  of  these  residues 
must  be  considered. 


42  THE    CHEMISTRY    OF 

Common  salt  is  the  safest,  and  perhaps  the  resi- 
dues from  acid  phosphate  are  next  in  order. 

The  tartrate,  lactate  and  acetate  of  sodium  are 
not  known  to  be  especially  hurtful.  As  the  im- 
portant constituent  of  Seidlitz  powders  is  Rochelle 
salt,  the  same  compound  as  that  resulting  from  the 
use  of  cream  of  tartar  and  "soda,"  it  is  not  likely  to 
be  very  deleterious,  taken  in  the  small  quantities 
in  which  even  habitual  "soda  biscuit"  eaters  take  it. 
p3ucte  '^^^  various  products  formed  by  the  chemical  de- 

composition of  alum  and  "soda"  are  possibly  the 
most  injurious,  as  the  sulphates  are  supposed  to  be 
the  least  readily  absorbed  salts.  Taking  into  con- 
sideration the  advantage  given  by  the  insolubility 
of  cream  of  tartar  in  cold  water,  and  the  compara- 
tively little  danger  from  its  derivative — Rochelle 
salt — it  would  seem  to  be,  on  the  whole,  the  best 
substance  to  add  to  the  soda  in  order  to  liberate 
the  gas;  but  the  proportions  should  be  chemically 
exact,  in  order  that  there  be  no  excess  of  alkali  to 
hinder  digestion.  Hence,  baking  powders  pre- 
pared by  weight  and  carefully  mixed,  are  a  great 
improvement  over  cream  of  tartar  and  "soda" 
measured  separately.  As  commonly  used,  the 
proportion  of  soda  should  be  a  little  less  than 
half.  The  table  on  page  23  gives  the  chemical  re- 
actions of  the  more  common  baking  powders. 


COOKING    AND    CLEANING. 


43 


Fats. 

Another  group  of  substances  which,  by  their 
slow  combustion  or  oxidation  in  the  animal  body, 
yield  carbon  dioxide  and  water  and  furnish  heat 
to  the  system,  is  called  fats.  These  comprise  the 
animal  fats — suet,  lard,  butter,  etc. — and  the  vege- 
table oils — olive  oil,  cottonseed  oil,  the  oily  matter 
in  com,  oats,  etc. 

Fats,  ordinarily  so  called,  are  simply  solidified 
oils,  and  oils  are  liquid  fats.  The  difference  be- 
tween them  is  one  of  temperature  only ;  for,  within 
the  body,  all  are  fluid.  In  this  fluid  condition,  they 
are  held  in  little  cells  which  make  up  the  fatty 
tissues. 

These  fatty  materials  all  have  a  similar  composi- 
tion, containing,  when  pure,  only  carbon,  hydro- 
gen, and  oxygen.  They  differ  from  starch  and 
sugar  in  the  proportion  of  oxygen  to  the  carbon 
and  hydrogen,  there  being  very  little  oxygen  rela- 
tively in  the  fatty  group,  hence  more  must  be 
taken  from  the  air  for  their  combustion. 


Composition 
of  Fats. 


Cis      Has  vJ2 
Stearic  Acid  in  Suet. 


Starch. 


One  pound  of  starch  requires  one  and  two-tenths 
pounds  of  oxygen,  while  one  pound  of  suet  re- 
quires about  three  pounds  of  oxygen  for  perfect 
combustion.    This  combination  of  oxygen  with  the 


Combustion 
of  Fats. 


44  THE    CHEMISTRY    OF 

excess  of  hydrogen,  as  well  as  with  the  excess  of 
carbon  results  in  a  greater  quantity  of  heat  from 
fat,  pound  for  pound,  than  can  be  obtained  from 
starch  or  sugar.  Recent  experiments  have  proved 
that  the  fats  yield  more  than  twice  as  much  heat  as 
the  carbohydrates;  hence  people  in  Arctic  regions 
require  large  amounts  of  fat,  and,  everywhere,  the 
diet  of  winter  should  contain  more  fat  than  that  of 
summer. 

While  the  chemical  expression  of  these  changes 
is  that  of  heat  produced,  it  must  be  remembered 
that  energy  or  work  done  by  the  body  is  included, 
and  that  both  fats  and  carbohydrates  are  the  source 
of  this  energy,  and  that  they  must  be  increased  in 
proportion  as  the  mechanical  work  of  the  body  in- 
creases. If  a  quantity  is  taken  at  any  one  time 
greater  than  the  body  needs  for  its  work,  the  sur- 
plus will  be  deposited  as  a  bank  account,  to  be 
drawn  from  in  case  of  any  lack  in  the  future  supply 
of  either. 

This  double  source  of  energy  has  a  large 
economic  value,  for  it  has  been  noticed  that  in  com- 
munities where  fats  are  dear,  the  required  amount 
of  heat-giving  and  energy-producing  food  is  made 
up  by  a  larger  proportion  of  the  cheaper  carbo- 
hydrates. This  prevents  too  large  a  draft  on  the 
bank  account.  It  has  also  been  noticed  that  wage- 
earners  do  use  a  large  proportion  of  fat,  whenever 
it  is  within  their  means. 


COOKING    AND    CLEANING. 


46 


Numerous  investigations  into  the  condition  of 
the  insane,  as  well  as  of  the  criminal  classes,  show 
the  results  of  too  little  nutrition  and  the  absence  of 
sufficient  fat.  The  diet  of  school  children  should 
be  carefully  regrilated  with  the  fat  supply  in  view. 
Girls,  especially,  show,  at  times,  a  dislike  to  fat  and 
an  overfondness  for  sugar.  They  should  have  the 
proper  proportion  of  fat  furnished  by  butter,  cream, 
or,  if  need  be,  in  disguised  form.  The  cook  must 
remember  that  the  butter  absorbed  from  her  cake 
tin  or  the  olive  oil  on  her  salad  is  food,  as  well  as 
the  flour  and  eggs. 

The  essential  oils,  although  very  important,  as 
will  be  shown  in  the  chapter  on  flavors,  occur  in 
such  small  quantities  that  they  need  not  be  con- 
sidered here,  except  by  way  of  caution.  These  oils 
are  all  volatile,  and,  therefore,  will  be  dissipated  by 
a  high  temperature. 

The  digestion  of  fats  is  mainly  a  process  of  emul- 
sion. With  the  intestinal  fluids,  the  bile,  especially, 
the  fats  form  an  emulsion  in  which  the  globules 
are  finely  divided,  and  rendered  capable  of  passing 
through  the  membranes  into  the  circulatory  sys- 
tem. The  change,  if  any,  is  not  one.  destructive 
of  the  properties  of  the  fatty  matters. 

If  we  define  cooking  as  the  application  of  heat, 
then  whatever  we  do  to  fats  in  the  line  of  cooking 
them  is  liable  to  hinder  rather  than  help  their  diges- 


Neccssity  of 
Fat  in  the 
Diet. 


The  Digestion 
of  Fat. 


46  COOKING    AND    CLEANING. 

tibility.    The  flavor  which  cooking  gives  to  food 
materials  containing  fat  is,  in  general,  due  not  to 
any  flavor  of  the  fat  but  to  substances  produced 
in  the  surrounding  tissues, 
ffi^h'flm-  ^dXs  may  be  heated  to  a  temperature  far  above 

^rature  on  that  of  boiling  Water  without  showing  any  change ; 

but  there  comes  a  point,  different  for  each  fat, 
where  reactions  take  place,  the  products  of  which 
irritate  the  mucous  membranes  and,  therefore,  in- 
terfere with  digestion.  It  is  the  volatile  products  of 
such  decomposition  which  cause  the  familiar  action 
upon  the  eyes  and  throat  during  the  process  of 
frying,  and,  also,  the  tell-tale  odors  throughout  the 
house.  The  indigestibility  of  fatty  foods,  or  foods 
cooked  in  fat,  is  due  to  these  harmful  substances 
produced  by  the  too  high  temperature.  It  must 
not  be  inferred  from  what  has  been  said  that  the 
oxidation  of  starch  and  fat  is  the  only  source  of 
heat  in  the  animal  body.  A  certain  quantity  is  un- 
doubtedly derived  from  the  chemical  changes  of 
the  other  portions  of  food,  but  the  chemistry  of 
these  changes  is  not  yet  fully  understood. 


CHAPTER   IV. 


Nitrogenous  Constituents. 

THE  animal  body  is  a  living  machine,  capable 
of  doing  work — raising  weights,  pulling  loads, 
and  the  like.  The  work  of  this  kind  which  it  does 
can  be  measured  by  the  same  standard  as  the  work 
of  any  machine,  i.  e.,  by  the  mechanical  unit  of 
energy — the  foot-ton. 

The  power  to  do  mechanical  work  comes  from 
the  consumption  of  fuel, — the  burning  of  wood, 
coal  or  gas ;  and  this  potential  energy  of  fuel  is  often 
expressed  in  units  of  heat  or  calories,  a  calorie  being 
nearly  the  amount  of  heat  required  to  raise  two 
quarts  of  water  oiie  degree  Fahrenheit.  The  ani- 
mal body  also  requires  its  fuel,  namely  food,  in 
order  to  do  other  work — its  thinking,  its  talking  or 
even  its  worrying. 

The  animal  body  is  more  than  a  machine.  It 
requires  fuel  to  enable  it  not  only  to  work  but  also 
to  live,  even  without  working.  About  one-third  of 
the  food  eaten  goes  to  maintain  its  life,  for  while 
the  inanimate  machine  is  sent  periodically  to  the 
repair-shop,  the  living  machine  must  do  its  own 


Animal  Body 
a  Machine. 


Calories. 


Need  of  Body 
Fuel. 


Waste-Re- 
pair. 


48  THE    CHEMISTRY    OF 

repairing,  day  by  day,  and  minute  by  minute. 
Hence  it  is  that  the  estimations  of  the  fuel  and  re- 
pair material  needed  to  keep  the  living  animal  body 
in  good  working  and  thinking  condition  are,  in  the 
present  state  of  our  knowledge,  somewhat  empir- 
ical; but  it  is  believed  that,  within  certain  wide 
limits,  useful  calculations  can  be  made  by  any  one 
willing  to  give  a  little  time  and  thought  to  the  sub- 
ject. Our  knowledge  may  be  rapidly  increased  if 
such  study  is  made  in  many  localities  and  under 
varying  circumstances. 

The  adult  animal  lives,  repairs  waste,  and  does 
work;  while  the  young  animal  does  all  these  and 
more — it  grows.  For  growth  and  work  something 
else  is  needed  beside  starch  and  fat.  The  muscles 
are  the  instruments  of  motion,  and  they  must  grow 
and  be  nourished,  in  order  that  they  may  have 
power.  The  nourishment  is  carried  to  them  by  the 
blood  in  which,  as  well  as  in  muscular  tissue,  there 
is  found  an  element  which  we  have  not  heretofore 
considered,  namely,  nitrogen.  It  has  been  proved 
that  the  wear  and  tear  of  the  muscles  and  brain 
causes  the  liberation  of  nitrogenous  compounds, 
which  pass  out  of  the  system  as  such,  and  this  loss 
must  be  supplied  by  the  use  of  some  kind  of  food 
which  contains  nitrogen.  Starch  and  fat  do  not 
contain  this  element;  therefore  they  cannot  furnish 
it  to  the  blood. 


COOKING    AND    CLEANING.  49 

Nitrogenous  food-stuffs  comprise  at  least  two     £iTtX 
large  groups,  the  Albumins  or  Proteids  and  the 
Albuminoids. 

Albumins. 

The  Albumins  in  some  form  are  never  absent 
from  animal  and  vegetable  organisms.  They  are 
more  abundant  in  animal  flesh  and  in  the  blood. 
Tlie  typical  food  of  this  class  is  the  white  of  tgg, 
which  is  nearly  pure  albumin.  Other  common  arti- 
cles of  diet  belonging  to  this  group  are  the  casein 
of  milk,  the  musculin  of  animal  flesh,  the  gluten  of 
wheat,  and  the  legumin  of  peas  and  beans. 

Egg  albumin  is  soluble  in  cold  water,  but  coagu- 
lates at  about  i6o  degrees  F.  At  this  point  it  is 
tender,  jelly-like,  and  easily  digested,  while  at  a 
higher  temperature  it  becomes  tough,  hard  and  sol- 
uble with  difflculty. 

The  albumin  of  flesh  is  contained  largely  in  the 
blood;  therefore  the  juices  of  meat  extracted  in  cold 
water  form  an  albuminous  solution.  If  this  be 
heated  to  the  right  temperature  the  albumin  is 
coagulated  and  forms  the  "scum"  which  many  a 
cook  skims  off  and  throws  away.  In  doing  this 
she  wastes  a  large  portion  of  the  nutriment.  She 
should  retain  this  nutrition  in  the  meat  by  the  quick 
coagulation  of  the  albumin  of  the  exterior,  which 
will  prevent  further  loss,  or  use  the  nutritive  solu- 


60 


THE    CHEMISTRY    OF 


Collagen. 


Cooking  of 

Nitrogenous 

Food-Stufis. 


tion  in  the  form  of  soups  or  stews.  "Clear  soups" 
have  lost  much  of  their  nutritive  value  and,  there- 
fore, belong  among  the  luxuries. 

Albuminoids. 

The  animal  skeleton — horns,  bones,  cartilage, 
connective  tissue,  etc,  contain  nitrogenous  com- 
pounds which  are  converted  by  boiling  into  sub- 
stances that  form  with  water  a  jelly-like  mass. 
These  are  known  as  the  gelatins. 

The  chief  constituent  of  the  connective  tissues  is 
collagen.  This  is  insoluble  in  cold  water,  but  in  hot 
water  becomes  soluble  and  yields  gelatine.  Colla- 
gen swells  when  heated  and  when  treated  with 
dilute  acids.  Steak  increases  in  bulk  when  placed 
over  the  coals,  and  tough  meat  is  rendered  tender 
by  soaking  in  vinegar.  Freshly  killed  meat  is  tough, 
for  the  collagen  is  dr}^  and  hard.  In  time  it  becomes 
softened  by  the  acid  secretions  brought  about 
through  bacterial  action,  and  the  meat  becomes 
tender  and  easily  masticated.  Tannic  acid  has  the 
opposite  effect  upon  collagen,  hardening  and 
shrinking  it.  This  eflfect  is  taken  advantage  of  in 
tanning,  and  is  the  disadvantage  of  boiled  tea  as 
a  beverage. 

Cooking  should  render  nitrogenous  food  more 
soluble  because  here,  as  in  every  case,  digestibility 
means  solubility.     Therefore,  when  the  white  of 


COOKING    AND    CLEANING.  61 

tgg  (albumin),  the  curd  of  milk  (casein),  or  the  glu- 
ten of  wheat  are  hardened  by  heat,  a  much  longer 
time  is  required  to  effect  solution. 

As  previously  stated,  <tgg  albumin  is  tender  and  Eggs. 
jelly-like  when  heated  from  i6o  degrees  to  i8o  de- 
grees. This  fact  should  never  be  forgotten  in  the 
cooking  of  eggs.  Raw  eggs  are  easily  digested 
and  are  rich  in  nutrition;  when  heated  just  enough 
to  coagulate  the  albumin  or  "the  white,"  their  di- 
gestibility is  not  materially  lessened;  but  when 
boiled  the  albumin  is  rendered  more  difficultly 
soluble. 

To  secure  the  greatest  digestibility  in  combina- 
tion with  palatibility,  they  may  be  put  into  boiling 
water,  placed  where  the  temperature  can  be  kept 
below  i8o  degrees,  and  left  from  ten  to  fifteen  min- 
utes, or  even  longer,  as  the  albumin  will  not  harden 
and  the  yolk  will  become  mealy. 

To  fry  eggs  the  fat  must  reach  a  temperature — 
300  degrees  or  over — far  above  that  at  which  the 
albumin  of  the  egg  becomes  tough,  hard,  and  well- 
nigh  insoluble. 

The  oyster,  though  not  rich  in  nutrition,  is  read-  Oysten 
ily  digested  when  raw  or  slightly  warmed.  When 
fried  in  a  batter,  it  is  so  protected  by  the  water  in 
the  dough  that  the  heat  does  not  rise  high  enough 
to  render  insoluble  the  albuminous  morsel  within. 
Frying  in  crumbs  (in  which  there  is  always  30  to  40 


62 


THE    CHEMISTRY    OF 


Casein. 


Legumin. 


per  cent  water,  even  though  the  bread  be  dry)  is 
another  though  less  efficient  method  of  protection 
for  the  albumin.  Com  meal,  often  used  as  a  coat- 
ing, contains  lo  to  12  per  cent  of  water. 

Experiments  on  the  digestibility  of  gluten  have 
proved  that  a  high  temperature  largely  decreases 
its  solubility.  Subjected  to  artificial  digestion  for 
the  same  length  of  time,  nearly  two  and  one  half 
times  as  much  nitrogen  was  dissolved  from  the  raw 
gluten  as  from  that  which  had  been  baked.* 

When  gluten  is  combined  with  starch,  as  in  the 
cereals,  the  difficulties  of  correct  cooking  are  many, 
for  the  heat  which  increases  the  digestibility  of  the 
starch  decreases  that  of  the  gluten. 

The  same  principle  applies  to  casein — the  albu- 
minous constituent  of  milk.  There  seems  to  be  no 
doubt  that  boiling  decreases  its  solubility,  and,  con- 
sequently, its  digestibility  for  persons  of  delicate 
digestive  power. 

The  cooking  of  beans  and  all  leguminous  vege- 
tables should  soften  the  cellulose  and  break  up 
the  compact  grains  of  starch.  Vegetables  should 
never  be  cooked  in  hard  water,  for  the  legumin  of 
the  vegetable  forms  an  insoluble  compound  with 
the  lime  or  magnesia  of  the  water. 

In  the  case  of  flesh  the  cooking  should  soften 


*The  Effect  of  Heat  up(jn  the  Digestibility  of  Gluten,  by  Ellen  H.  Richards. 
A.  M.,  S.  B.,  and  Elizabeth  Mason,  A.  B.    Technology  Quarterly,  Vol.  vii.,  63. 


COOKING    AND    CLEANING.  63 

and  loosen  the  connective  tissue,  so  that  the  little 
bundles  of  fibre  which  contain  the  nutriment  may 
fall  apart  easily  when  brought  in  contact  with  the 
teeth.  Any  process  which  toughens  and  hardens 
the  meat  should  be  avoided. 

Whenever  it  is  desired  to  retain  the  juices  within 
the  meat  or  fish,  it  should  be  placed  in  boiling  water 
that  the  albumin  of  the  surface  may  be  hardened 
and  so  prevent  the  escape  of  the  albumin  of  the 
interior.  The  temperature  should  then  be  low- 
ered and  kept  between  i6o  and  i8o  degrees 
during  the  time  needed  for  the  complete  break- 
ing down  of  the  connective  tissues.  When 
the  nutriment  is  to  be  used  in  broths,  stews 
or  soups,  the  meat  should  be  placed  in  cold 
water,  heated  very  slowly  and  the  temperature 
not  allowed  to  rise  above  i8o  degrees  until  the 
extraction  is  complete.  To  dissolve  the  softened 
collagen,  a  temperature  of  212  degrees  is  necessary 
for  a  short  time. 

The  object  of  all  cooking  is  to  make  the  food-  object  oi 
stuffs  more  palatable  or  more  digestible  or  both  °^  '"** 
combined. 

In  general,  the  starchy  foods  are  rendered  more 
digestible  by  cooking;  the  albuminous  and  fatty 
foods  less  digestible.  y?- 

The  appetite  of  civilized  man  craves  and  custom 
encourages  the  putting  together  of  raw  materials 


64  THE    CHEMISTRY    OF 

of  such  diverse  chemical     composition  that  the 
processes  of  cooking  are  also  made  complex. 

Bread — the  staff  of  life — requires  a  high  degree 
of  heat  to  kill  the  plant-life,  and  long  baking  to 
prepare  the  starch  for  solution;  while,  by  the  same 
process,  the  gluten  is  made  less  soluble. 

Fats,  alone,  are  easily  digested,  but  in  the  ordi- 
nary method  of  frying,  they  not  only  become  de- 
composed themselves,  and,  therefore,  injurious; 
but  they  also  prevent  the  necessary  action  of  heat, 
or  of  the  digestive  ferments  upon  the  starchy  ma- 
terials with  which  the  fats  are  mixed. 
Pastry.  Pastry  owes  its  harmful  character  to  this  inter- 

ference of  fat  with  the  proper  solution  of  the  starch. 
Good  pastry  requires  the  intimate  mixture  of  flour 
with  solid  fat.  The  starch  granules  of  the  flour 
must  absorb  water,  swell,  and  burst  before  they  can 
be  dissolved.  The  fat  does  not  furnish  enough 
water  to  accomplish  this,  and  it  so  coats  the  starch 
granules  as  to  prevent  the  sufficient  absorption  of 
water  in  mixing,  or  from  the  saliva  during  mas- 
tication. This  coating  of  fat  is  not  removed  till 
late  in  the  process  of  digestion.  The  same  effect  is 
produced  by  the  combining  of  flour  and  fat  in 
made  gravies. 
Effect  of  The  effect  of  cooking  upon  the  solubility  of  the 

Cooking.  three     important  food-principals  may  be  broadly 

stated  thus : — 


COOKING    AND    CLEANING.  55 

Starchy  foods  are  made  more  soluble  by  long 
cooking  at  moderate  temperatures  or  by  heat 
high  enough  to  dextrinize  a  portion  of  the  starch, 
as  in  the  brown  crust  of  bread. 

Nitrogenous  foods.  The  animal  and  vegetable 
albumins  are  made  less  soluble  by  heat;  the  animal 
albuminoids  more  soluble. 

Fats  are  readily  absorbed  in  their  natural  condi- 
tion, but  are  decomposed  at  very  high  temperatures 
and  their  products  become  irritants. 


CHAPTER  V. 

The  Art  of  Cooking. 
Flavors  and  Condiments. 

THE  science  as  well  as  the  art  of  cooking  lies  in 
the  production  of  a  subtle  something  which 
gives  zest  to  the  food  and  which,  though  infinites- 
imal in  quantity,  is  of  priceless  value.  It  is  the 
savory  potage,  the  mint,  anise  and  cummin,  the 
tasteful  morsel,  the  appetizing  odor,  which  is, 
rightly,  the  pride  of  the  cook's  heart. 
Flavors.  The  most  general  term  for  this  class  of  stimu- 

lating substances  is,  perhaps,  flavor — the  gout  of 
the  French,  the  Genus s-Mittel  (enjoyment-giver)  of 
the  Germans. 

The  development  of  this  quality  in  food — taste, 
savor,  relish,  flavor  or  what  not,  which  makes  "the 
mouth  water,"  depends,  in  every  case,  upon  chem- 
ical changes  more  subtle  than  any  others  known 
to  us.  The  change  in  the  coffee  berry  by  roasting 
is  a  familiar  illustration.  The  heat  of  the  fire  causes 
the  breaking  up  of  a  substance  existing  in  the  bern,' 
and  the  production  of  several  new  ones.  If  the 
heat  is  not  sufficient,  the  right  odor  will  not  be 


COOKING    AND    CLEANING.  57 

given ;  if  it  is  too  great,  the  aroma  will  be  dissipated 
into  the  air  or  the  compound  will  be  destroyed. 

This  is  an  excellent  illustration  of  the  narrow  Nature  of 
margin  along  which  success  lies.  It  is  also  chem- 
ically typical  of  the  largest  number  of  flavors, 
which  seem  to  be  of  tiie  nature  of  oils,  set  free  by 
the  breaking  up  of  the  complex  substances  of  which 
they  form  a  part  Nature  has  prepared  these  essen- 
tial oils  by  the  heat  of  the  sun.  They  give  the  taste 
to  green  vegetables;  while  in  fruits  they  are  present 
with  certain  acids,  and  both  together  cause  the 
pleasure-giving  and  therapeutic  effects  for  which 
fruit  is  noted. 

It  is  probable  that  the  flavors  of  roasted  corn, 
well-cooked  oatmeal,  toasted  bread,  also  belong  to 
this  class.  Broiled  steak  and  roasted  turkey  are 
also  illustrations,  and  with  coffee  show  how  easily 
the  mark  is  overstepped — a  few  seconds  too  long, 
a  very  few  degrees  too  hot,  and  the  delicate  morsel 
becomes  an  acrid,  irritating  mass. 

From  this  standpoint,  cooking  is  an  art  as  exact 
as  the  pharmacist's,  and  the  person  exercising  it 
should  receive  as  careful  preparation;  for  these 
flavors,  which  are  so  highly  prized,  are  many  of 
them  the  drugs  and  poisons  of  the  apothecary  and 
are  to  be  used  with  as  much  care.  This  is  an  addi- 
tional reason  for  producing  them  by  legitimate 
means  from  the  food  itself,  and  not  by  adding  the 


68 


THE    CHEMISTRY    OF 


Chemistry  of 
Flavors. 


Condiments 
and  their 
Efiect. 


crude  materials  in  quantities  relatively  enormous  to 
those  of  the  food  substances. 

The  chemistry  of  cooking  is  therefore  largely  the 
chemistry  of  flavor-production — the  application  of 
heat  to  the  food  material  in  such  a  way  as  to  bring 
about  the  right  changes  and  only  these. 

The  flavors  produced  by  cooking,  correctly  done, 
will  be  delicate  and  unobtrusive.  Usually,  except 
for  broiled  meats,  a  low  heat  applied  for  a  long 
time,  with  the  use  of  closed  cooking  vessels,  de- 
velops the  best  flavors;  while  quick  cooking,  which 
necessitates  a  high  temperature,  robs  the  fine  prod- 
ucts of  nature's  laboratory  of  their  choicest  ele- 
ments. Present  American  cookery,  especially,  sins 
in  this  respect.  Either  the  food  is  insipid  from  lack 
of  flavor  or  crudely  seasoned  at  the  last  moment. 

The  secret  of  the  success  of  our  grandmothers' 
cooking  lay  not  solely  in  the  brick  oven — in  the 
low,  steady  heat  it  furnished — but  in  the  care, 
thought,  and  infinite  pains  they  put  into  the  prep- 
aration of  their  simple  foods.  Compared  with 
these,  the  "one-minute"  cereals,  the  "lightning" 
pudding  mixtures  of  the  present  are  insipid,  or 
tasteless.  Experience  with  the  Aladdin  Oven  is  an 
education  in  flavor  production. 

Another  source  of  stimulating  flavor  is  found  in 
the  addition  of  various  substances  called  Condi- 
ments.    These  consist  of  materials,  of  whatever 


COOKING    AND    CLEANING.  69 

nature,  added  to  the  food  compounds,  to  give  them 
a  rehsh.  Their  use  is  legitimate ;  their  abuse,  harm- 
ful. The  effect  of  flavors  is  due  to  the  stimulation 
of  the  nerves  of  taste  and  smell.  Condiments  should 
be  used  in  a  way  to  cause  a  like  stimulation  of  the 
nerves.  If  they  are  added  to  food  materials  before 
or  during  the  cooking  process,  a  small  quantity 
imparts  a  flavor  to  the  entire  mixture.  If  added  to 
the  cooked  food,  a  larger  quantity  is  used  and  the 
effect  lasts,  not  only  while  the  food  is  in  contact 
with  the  nerves  of  the  mouth,  but  also  throughout 
the  digestive  tract,  causing  an  irritation  of  the 
mucous  membranes  themselves.  Tlie  tissues  be- 
come weakened,  and,  in  time,  lose  the  power  of 
normal  action. 

Cayenne  pepper  directly  applied  to  the  food, 
although  sometimes  a  help,  is  oftener  the  cause  in 
dyspepsia.  Highly  seasoned  food  tends  to  weaken 
the  digestion  in  the  end,  by  calling  for  more  secre- 
tion than  is  needed  and  so  tiring  out,  as  it  were, 
the  glands.  It  is  like  the  too  frequent  and  violent 
application  of  the  whip  to  a  willing  steed — ^by  and 
by  he  learns  to  disregard  it.  Just  enough  to  accom- 
plish the  purpose  is  nature's  economy. 

This  economy  is  quick  to  recognize  and  be  satis- 
fied with  a  food  which  is  easily  digested  without  im- 
pairing the  functional  powers  of  the  digestive 
fluids.    A  child  seldom  shows  a  desire  for  condi- 


eo 


THE    CHEMISTRY    OF 


ments  unless  these  have  been  first  unwisely  added 
by  adults.  Flavors  are  largely  odors,  or  odors  and 
tastes  combined,  and  act  upon  the  nervous  system 
in  a  natural  way.  Condiments,  in  many  cases,  are 
powerful,  stimulating  drugs,  exciting  the  inner  lin- 
ings of  the  stomach  to  an  increased  and  abnormal 
activity.  Medicinally  they  may  act  as  tonics.  The 
skill  of  the  cook  consists  in  steering  between  the 
two  digestion  possibilities^ — hinder  and  help. 

Some  relish-giving  substances,  as  meat  extracts, 
the  caffeine  of  cofifee,  theine  of  tea,  theo-bromine  of 
cocoa,  and  alcohol  of  wines  go  directly  into  the 
blood  and  here  act  upon  the  nervous  system.  They 
quicken  the  circulation  and,  therefore,  stimulate  to 
increased  activity.  The  cup  of  coffee  thus  drives 
out  the  feeHng  of  lassitude  from  wearied  nerves  and 
muscles.  Wine  should  never  be  treated  as  an  arti- 
cle of  diet,  but  as  a  Genuss-Mittel. 

The  secret  of  the  cooking  of  vegetables  is  the 
judicious  production  of  flavor.  In  this  the 
French  cook  excels.  She  adds  a  little  meat  juice  to 
the  cooked  vegetables,  thus  obtaining  the  desired 
flavor  with  the  cheaper  nutritious  food.  This  wise 
use  of  meats  for  flavor,  while  the  actual  food  value 
is  made  up  from  the  vegetable  kingdom,  is  an  im- 
portant item  in  public  kitchens,  institutions,  or 
wherever  expense  must  be  closely  calculated. 

In  the  study  of  economy,  flavor-creation  is  of  the 


COOKING    AND    CLEANING.  61 

utmost  importance.  In  foods,  as  everywhere, 
science  and  art  must  supplement  the  purse,  making 
the  few  and  cheaper  materials  necessary  for  nutri- 
tion into  a  variety  of  savory  dishes.  Without  the 
appetizing  flavor,  many  a  combination  of  food  ma- 
terials is  utterly  worthless,  for  this  alone  stimu- 
lates the  desire  or  appetite,  the  absence  of  which 
may  prevent  digestion.  Food  which  pleases  the 
palate,  unless  this  has  been  abnormally  educated, 
is  usually  wholesome,  and  judgment  based  on 
flavor  is  normally  a  sound  one. 

Starch  may  be  cooked  according  to  the  most  ap-  ^°"Di"estioa 
proved  methods;  but,  if  there  is  no  saliva,  the  starch 
is  without  food  value.  The  piece  of  meat  may  be 
done  to  a  turn;  but,  if  there  is  no  gastric  juice  in 
the  stomach,  it  will  not  be  dissolved,  and  hence  is 
useless.  A  homely  illustration  will  best  serve 
our  turn, — a  cow  may  retain  her  milk  by 
force  of  will.  It  is  well  known  how  much 
a  contented  mind  has  to  do  with  her  readi- 
ness to  give  milk  and  the  quantity  of 
milk  she  will  yield.  The  various  glands  of  the 
human  body  seem  to  have  a  like  action.  The  dry 
mouth  fails  to  moisten  the  food,  and  the  stimulating 
flavor  is  lost.  On  the  other  hand  the  mouth 
"waters,"  and  food  is  soon  digested.  The  cow  may 
be  utterly  foolish  and  whimsical  in  her  ideas — so 
may  persons.    There  may  not  be  the  least  reason 


62 


THE    CHEMISTRY    OF 


Serring 


Discretion  in 
Cooking. 


Bacterial 
Action  Pro- 
duces 
Flavors. 


Cooking  an 
Art. 


why  a  person  should  turn  away  from  a  given  food, 
but  if  he  does ?    He  suffers  for  his  whims. 

Hence  the  cook's  art  is  most  important,  for  its 
results  must  often  overcome  adverse  mental  con- 
ditions by  nerve-stimulating  flavors.  The  art 
of  serving,  though  out  of  place  here,  should  be  at- 
tentively studied  with  the  effect  on  the  appetite 
especially  in  view.  This  is  of  the  utmost  im- 
portance in  connection  with  hospital  cooking. 

Specific  flavors,  though  agreeable  in  themselves, 
should  be  used  with  discretion.  In  Norway,  the 
salmon  is  designedly  cooked  so  as  not  to  retain 
much  of  its  characteristic  savor,  for  this  is  too  de- 
cided a  flavor  for  an  article  of  daily  diet.  In  soups 
and  stews  a  "bouquet"  of  flavors  is  better  than  the 
prominence  of  any  one,  although  certain  favorite 
dishes  may  have  a  constant  flavor. 

Nature  has  produced  many  flavors  and  guarded 
well  the  secret  of  their  production;  but  science  is 
fast  discovering  their  sources,  as  bacterial  life  and 
action  are  better  understood.  Now,  the  "June 
flavor"  of  butter  may  be  produced  in  December, 
by  inoculating  milk  with  the  right  "butter 
bacillus." 

Cooking  has  thus  become  an  art  worthy  the  at- 
tention of  intelligent  and  learned  women.  The 
laws  of  chemical  action  are  founded  upon  the  laws 
of  definite  proportions,  and  whatever  is  added  more 


COOKING    AND    CLEANING.  68 

than  enough,  is  in  the  way.  The  head  of  every 
household  should  study  the  condition  of  her  fam- 
ily, and  tempt  them  with  dainty  dishes,  if  that  is 
what  they  need.  Let  her  see  to  it  that  no  burst  of 
ill  temper,  no  sullen  disposition,  no  intemperance 
of  any  kind  be  caused  by  her  ignorance  or  her  dis- 
regard of  the  chemical  laws  governing  the  reactions 
of  the  food  she  furnishes. 

When  this  science  and  this  art  takes  its  place  be- 
side the  other  sciences  and  other  arts,  one  crying 
need  of  the  world  will  be  satisfied. 

We  have  now  considered  the  three  classes  of 
food  in  one  or  more  of  which  all  staple  articles  of 
diet  may  be  placed — the  carbohydrates  (starch  and 
sugar),  the  fats  and  the  nitrogenous  material.  Some 
general  principles  of  diet,  indicated  by  science,  re- 
main to  be  discussed. 

Diet. 

All  preparation  of  food-stufifs  necessary  to  make  ^°^^P^*  °' 
them  into  suitable  food  for  man  comes  under  the  s*"^*- 
head  of  what  has  been  called  "external  digestion." 
The  processes  of  internal  digestion  begin  in  the 
mouth.  Here  the  saliva  not  only  lubricates  the 
finely  divided  portions  of  the  food  materials,  but, 
in  the  case  of  starch,  begins  the  process  of  chang- 
ing the  insoluble  starch  into  a  soluble  sugar.  This 
process  is  renewed  in  the  small  intestine.    The  fats 


64 


THE    CHEMISTRY    OF 


Mastication. 


Pepsin  and 
Aad  of 
Stomach. 


Decomposi- 
tion Products. 


are  emulsified  in  the  small  intestine,  and,  with  the 
soluble  carbohydrates,  are  here  largely  absorbed. 

All  the  chemical  changes  which  the  nitrogenous 
food  stuffs  undergo  are  not  well  understood.  Such 
food  should  be  finely  comminuted  in  the  mouth, 
because,  as  before  stated,  chemical  action  is  rapid 
in  proportion  to  the  fineness  of  division;  but  it  is 
in  the  stomach  that  the  first  chemical  change 
occurs. 

The  chief  agents  of  this  change  are  pepsin 
and  related  substances,  aided  by  the  acid  of  the 
gastric  juice;  these  together  render  the  nitrogenous 
substance  soluble  and  capable  of  passing  through 
the  membranes.  Neither  seems  able  to  do  this 
alone,  for  if  the  acid  is  neutralized,  action  ceases; 
and  if  pepsin  is  absent,  digestion  does  not  take 
place. 

Decompositions  of  a  very  complex  kind  occur, 
peptones  are  formed  which  are  soluble  compounds, 
and  the  nitrogen  finally  passes  out  of  the  system  as 
^xrea,  being  separated  by  the  kidneys,  as  carbon  di- 
oxide is  separated  by  the  lungs. 

One  of  the  most  obvious  questions  is:  Which  is 
best  for  human  food — starch  or  fat,  beans  and  peas, 
or  flesh?  As  to  starch  or  fat,  the  question  has  been 
answered  by  experience,  and  science  has  only  tried 
to  explain  the  reason.  The  colder  the  cHmate,  the 
more  fat  the  people  eat.    The  tropical  nations  live 


COOKING    AND    CLEANING. 


65 


chiefly  on  starchy  foods,  as  rice.  From  previous 
statements  it  will  be  seen  that  this  is  right  in  princi- 
ple. Fat  yields  more  heat  than  rice;  therefore  the 
inference  is  plain  that  in  the  cold  of  winter  fat  is 
appropriate  food,  while  in  the  heat  of  summer  rice 
or  some  other  starchy  food  should  be  substituted. 

The  diet  of  summer  should  also  contain  much 
fruit.  Increased  perspiration  makes  necessary  an 
increased  supply  of  water.  This  may  be  furnished 
largely  by  fruits,  and  with  the  water  certain  acids 
are  taken  which  act  as  correctives  in  the  digestive 
processes. 

No  evident  rule  can  be  seen  in  the  case  of  the 
albuminous  foods.  At  most,  the  class  can  be  di- 
vided into  three  groups.  The  first  includes  the  ma- 
terial of  vegetable  origin,  as  peas,  lentils,  and  the 
gluten  of  wheat.  The  second  comprises  the  white 
of  egg  and  the  curd  of  milk — material  of  animal 
origin.  The  third  takes  in  all  the  animal  flesh  used 
by  mankind  as  food. 

Considering  the  question  from  a  purely  chemical 
standpoint,  without  regarding  the  moral  or  social 
aspects  of  the  case,  two  views  stand  out  clearly: 
I  St.  If  the  stored-up  vegetable  matter  has  required 
the  force  derived  from  the  sun  to  prepare  it,  the 
tearing  apart  and  giving  back  to  the  air  and  earth 
the  elements  of  which  it  was  built  up  will  yield  the 
same  amount  of  force  to  whatever  tears  it  down; 


Seasonable 
Diet, 


Economy  of 
a  Mixed 
Diet. 


THE    CHEMISTRY    OF 


Food  of 
Young 
Animals. 


Need  of  Veg- 
etable Food. 


but  a  certain  amount  of  energy  must  be  used  up  in 
this  destruction.  2d.  If  the  animal,  having  accom- 
pHshed  the  decomposition  of  the  vegetable  and  ap- 
propriated the  material,  is  killed,  and  the  prepared 
nitrogenous  food  in  the  form  of  muscle  is  eaten  by 
man,  then  little  force  is  necessary  to  render  the 
food  assimilable ;  it  is  only  to  be  dissolved  in  order 
that  it  may  enter  into  the  circulation.  The  force- 
producing  power  is  not  lost;  it  is  only  transferred 
to  another  animal  body.  Hence  the  ox  or  the 
sheep  can  do  a  part  of  man's  work  for  him  in  pre- 
paring the  vegetable  food  for  use,  and  man  may 
thus  accomplish  more  than  he  otherwise  could. 
This  digestion  of  material  outside  of  the  body  is 
carried  still  further,  by  man,  in  the  manufacture  of 
partially  digested  foods, — "malted,"  "peptonized," 
"pre-digested,"  etc.  Exclusive  use  of  these  is 
fraught  with  danger,  for  the  organs  of  digestion 
lose  power,  if  that  which  they  have,  however 
little,  be  long  unused. 

Nearly  all,  if  not  all,  young  animals  live  on  food 
of  animal  origin.  The  young  of  the  human  race 
live  on  milk;  but  it  has  been  found  by  experience 
that  milk  is  not  the  best  food  for  the  adult  to  live 
upon  to  the  exclusion  of  all  else.  It  is  not  con- 
ducive to  quickness  of  thought  or  general  bodily 
activity. 

Experience  leads  to  the  conclusion  that  mankind 


COOKING    AND    CLEANING.  67 

needs  some  vegetable  food.  Two  facts  sustain  this 
inference.  The  digestive  organs  of  the  herbivorous 
animals  form  fifteen  to  twenty  per  cent  of 
the  whole  weight  of  the  body.  Those  of 
the  carnivorous  animals  form  five  to  six 
per  cent,  those  of  the  human  race,  about 
eight  per  cent.  The  length  of  the  canal 
through  which  the  food  passes  varies  in  about  the 
same  ratio  in  the  three  classes.  A  mixed  diet  seems 
to  be  indicated  as  desirable  by  every  test  which  has 
been  appHed;  but  the  proportions  in  which  the 
vegetable  and  animal  food  are  to  be  mingled,  as 
well  as  the  relative  quantities  of  carbonaceous  and 
nitrogenous  material  which  will  give  the  best  effi- 
ciency to  the  human  machine  are  not  so  easily 
determined. 

Nature  seems  to  have  made  provision  for  the  ex-  water  and 
cess  of  heat  resulting  from  the  oxidation  of  too 
much  starch  or  fat,  by  the  ready  means  of  evapora- 
tion of  water  from  the  surface;  this  loss  of  water 
being  supplied  by  drinking  a  fresh  supply,  which 
goes,  without  change,  into  the  circulation.  The 
greater  the  heat,  the  greater  the  evaporation ;  hence 
the  importance  of  water  as  an  article  of  diet,  espe- 
cially for  children,  must  not  be  overlooked.  For 
an  active  person,  the  supply  has  been  estimated  at 
three  quarts  per  day.  Water  is  the  heat  regulator 
of  the  animal  body.     An  article  entitled  "Water 


Air  as  Food. 


68 


THE    CHEMISTRY    OF 


Dangers  ot 

Excess. 


Dietaries. 


and  Air  as  Food,"*  by  one  of  the  authors  of  this 
book,  treats  this  subject  more  thoroughly. 

While  dangerous  disease  seldom  results  from 
eating  an  excess  of  starch  or  fat,  because  the  por- 
tion not  wanted  is  rejected  as  if  it  were  so  much 
sand,  many  of  the  most  complicated  disorders  do 
result  from  an  excess  of  nitrogenous  diet. 

The  readiness  with  which  such  substances  under- 
go putrefaction,  and  the  many  noxious  products  to 
which  such  changes  give  rise,  should  lead  us  to  be 
more  careful  as  to  the  quantity  of  this  food. 

From  experiments  made  by  the  best  investiga- 
tors, it  seems  probable  that  only  one  third  of  the 
estimated  daily  supply  of  food  is  available  for  ki- 
netic force;  that  is,  that  only  about  one  third  of  the 
total  energy  contained  in  the  daily  food  can  be  util- 
ized in  digging  trenches,  carrying  bricks,  climbing 
mountains,  designing  bridges,  or  writing  poems 
and  essays.  The  other  two  thirds  is  used  up  in  the 
internal  work  of  the  body — the  action  of  the  heart, 
lungs,  and  the  production  of  the  large  amount  of 
heat  necessary  to  life. 

It  has  been  estimated  that  a  growing  person 
needs  about  one  part  of  nitrogenous  food  to  four  of 
starch  and  fat;  a  groivn  person,  one  part  nitro- 
genous to  five  or  six  of  starch  and  fat.    If  this  is 

*  Rumford  Kitchen  Leaflet,  No.  6,  A  merican  KUchtn  Magazine,  Vol.  IV., 
aS7- 


COOKING    AND    CLEANING.  69 

true,  then  we  may  make  out  a  life  ration,  or  that 
amount  of  food  which  is  necessary  to  keep  the 
human  machine  in  existence. 

For  this  cHmate,  and  for  the  habits  of  our  people, 
we  have  estimated  this  life  ration  as  approximately: 

Protcid.  Fat.  Carbohydrates.  Calories. 

75  grams.  40  grams.  325  grams.  3,000. 

The  amount  of  energy  given  out  in  the  form  of 
work  cannot  exceed  the  amount  of  energy  taken  in 
in  the  form  of  food;  so  this  life  ration  is  increased 
to  make  a  maximum  and  minimum  for  a  work 
ration.  For  professional  or  literary  persons  the 
following  may  be  considered  a  sufficient  maximum 
and  minimum: 


Proteid. 

Fat. 

Carbohydrates. 

Calories. 

i«5  grams. 

125  grams. 

450  grams. 

3.500. 

no  grams. 

90  grams. 

420  grams. 

3,000. 

For  hard  manual  labor  about  one-third  is  to  be 
added  to  the  above  rations.  An  examination  of  the 
actual  dietaries  of  some  of  the  very  poor  who  eat 
just  enough  to  live,  without  doing  any  work, 
shows  that  in  twelve  cases  the  average  diet  was : 

Proteid.  Fat.  Carbohydrates.  Calories. 

31  grams.  81  grams.  272  grams.  2,257. 

For  further  information  on  these  points  see  the 
list  of  works  at  the  end  of  this  book. 

The  first  office  of  the  food,  then,  is  to  keep  the     offices  ot 
human  body  in  a  high  condition  of  health;  the 
second,  to  enable  it  to  exert  force  in  doing  the  work 


Food. 


70  COOKING   AND    CLEANING. 

of  the  world ;  and  a  third,  the  value  of  which  it  is 
hardly  possible  to  estimate,  is  to  furnish  an  im- 
portant factor  in  the  restoration  of  the  body  to  nor- 
mal condition,  when  health  is  lost  In  sickness, 
far  more  than  in  health,  a  knowledge  of  the  right 
proportions  of  the  essential  food  substances,  and  of 
the  absolute  quantity  or  food  value  given,  is  im- 
portant. How  many  a  life  has  been  lost  because  of 
a  lack  of  this  knowledge  the  world  will  never  know. 


PART  II. 
THE  CHEMISTRY  OF  CLEANING. 


CHAPTER  I. 
Dust. 


MANY  a  housewife  looks  upon  dust  as  her  in- 
veterate enemy  against  whom  incessant  war- 
fare brings  only  visible  defeat.  Between  the  battles, 
let  us  study  the  enemy  —  the  composition  of  his 
forces,  his  tactics,  his  ammunition,  in  order  that 
we  may  find  a  vantage  ground  from  which  to  direct 
our  assault,  or  from  which  we  may  determine 
whether  it  is  really  an  enemy  which  we  are  fighting. 

The  Century  dictionary  defines  dust  as  "Earth,  Definition  of 
or  other  matter  in  fine  dry  particles  so  attenuated 
that  they  can  be  raised  and  carried  by  the  wind." 
This  suggests  that  dust  is  no  modem  product  of 
the  universe.  Indeed,  its  ancestry  is  hidden  in 
those  ages  of  mystery  before  man  was.  Who  can 
say  that  it  does  not  reach  to  that  eternity  which  can 
be  designated  only  by  "In  the  beginning?" 


72  THE    CHEMISTRY    OF 

Tyndall  proved  by  delicate  experiments  that 
when  all  dust  was  removed  from  the  track  of  a 
beam  of  light,  there  was  darkness.  So  before  the 
command  "Let  there  be  light,"  the  dust-condition 
of  light  must  have  been  present.  Balloonists  find 
that  the  higher  they  ascend  the  deeper  the  color  of 
the  sky.  When  at  a  distance  of  some  miles,  the 
sky  is  nearly  black,  there  is  so  little  dust  to  scatter 
the  rays  of  light.  If  the  stellar  spaces  are  dustless, 
they  must  be  black  and,  therefore,  colorless.  The 
moisture  of  the  air  collects  about  the  dust-particles 
giving  us  clouds  and,  with  them,  all  the  glories  of 
sunrise  and  sunset.  Fogs,  too,  are  considered  to 
be  masses  of  "water-dust,"  and  ships  far  out  at  sea 
have  had  their  sails  colored  by  this  dust,  while  sail- 
ing through  banks  of  fog.  Thinking,  now,  of  the 
above  definition,  it  may  be  said  that  the  earth,  in 
its  final  analysis,  must  be  dust  deposited  during 
past  ages;  that  to  dust  is  due  the  light  necessary 
to  life,  and  that  without  it  certain  phenomena  of 
nature — clouds,  color,  fog,  perhaps,  even  rain  and 
snow  could  not  exist. 

It  behooves  us,  then,  as  inhabitants  of  this  dust- 
formed  and  dust-beautified  earth  to  speak  well  of 
our  habitation.  We  have  found  no  enemy  yet. 
The  enemy  must  be  lurking  in  the  "other  matter." 
This  the  dictionary  says  is  in  powdered  form,  car- 
ried by  the  air,  and,  therefore,  at  times  existent  in 


COOKING    AND    CLEANING. 


73 


it,  as  has  been  seen.  A  March  wind  gives  sensible 
proof  of  this,  but  what  about  the  quiet  air,  whether 
out  of  doors  or  in  our  houses? 

An  old  writer  has  said:  "The  sun  discovers 
atonies,  though  they  be  invisible  by  candle-light, 
and  makes  them  dance  naked  in  his  beams."  Those 
sensible  particles  with  these  "atomes,"  which  be- 
come visible  in  the  track  of  a  beam  of  light  when- 
ever it  enters  a  darkened  room,  make  up  the  dust 
whose  character  is  to  be  studied. 

Astronomers  find  meteoric  dust  in  the  atmos- 
phere. When  this  falls  on  the  snow  and  ice  fields 
of  the  Arctic  regions,  it  is  readily  recognized.  The 
eruption  of  Krakatoa  proved  that  volcanic  dust  is 
disseminated  world-wide.  Dust  contains  mineral 
matter,  also,  from  the  wear  and  tear  of  nature's 
forces  upon  the  rocks,  bits  of  dead  matter  given  off 
by  animal  and  vegetable  organisms,  minute  fibres 
from  clothing,  the  pollen  of  plants,  the  dry  and  pul- 
verized excrement  of  animals.  These  constituents 
are  easily  detected — are  they  all? 

Let  a  mixture  of  flour  and  water  stand  out-of- 
doors,  leave  a  piece  of  bread  or  bit  of  cheese  on 
the  pantry  shelves  for  a  week.  The  mixture  fer- 
ments, the  bread  and  cheese  mold.  Formerly,  these 
changes  were  attributed  to  the  "access  of  air" — i.  e., 
to  the  action  upon  the  substances,  of  the  oxygen  of 
the  air;  later  experiments  have  proved  that  if  the 


Visible  and 

Invisible 

Dust. 


Composition 
of  Dust 


Dust  Plants 


74  THE    CHEMISTRY    OF 

air  be  previously  passed  through  a  cotton-wool 
filter  it  will  cause  no  change  in  the  mixture.  The 
oxygen  is  not  filtered  out,  so  it  cannot  be  the  cause 
of  the  fermentation.  Now,  such  phenomena  of 
fermentation  are  known  to  be  caused  by  minute 
vegetable  organisms  which  exist  everywhere  in  the 
air  and  settle  from  it  when  it  becomes  dry  and  still. 
They  are  molds,  yeasts  and  bacteria.  All  are  mi- 
croscopic and  many  sub-microscopic.  They  are 
found  wherever  the  atmosphere  extends — some 
inches  below  the  surface  of  the  ground  and 
some  miles  above  it,  although  on  the  tops  of  the 
highest  mountains  and,  perhaps,  far  out  at  sea, 
the  air  is  practically  free  from  earthly  dust, 
and  therefore  nearly  free  from  these  forms.  The 
volcanic  dust  of  the  upper  air  does  not  appear  to 
contain  them.  They  are  all  spoken  of  as  "germs," 
because  they  are  capable  of  developing  into  grow- 
ing forms.  All  are  plants  belonging  to  the  fungi; 
in  their  manner  of  life  essentially  like  the  plants 
we  cherish,  requiring  food,  growing,  and  repro- 
ducing their  kind.  They  require  moisture  in  order 
to  grow  or  multiply;  but,  like  the  seeds  of  higher 
plants,  can  take  on  a  condition  calculated  to  resist 
hard  times  and  endure  these  for  long  periods;  then 
when  moisture  is  furnished,  they  immediately 
spring  into  growth.  In  the  bacteria  these  spores 
are    a    resting    stage,    not    primarily    reproduc- 


COOKING    AND    CLEANING. 


75 


tive;  while,  in  molds,  they  bring  forth  an  active, 
growing  plant. 

The  common  puff-ball  (Lycoperdon),  the  "smoke"  Spores, 
ball  of  the  country  child,  well  illustrates  both  vege- 
tative and  spore  stages.  This  belongs  to  the  fungi, 
is  closely  related  to  the  molds,  and  consists  of  a 
spherical  outer  wall  of  two  layers,  enclosing  tissues  ^ 
which  form  numerous  chambers  with  membraneous 
partitions.  Within  these  chambers  are  formed  the 
reproductive  cells  or  spores.  When  ripe,  the  mass 
becomes  dry,  the  outer  layer  of  the  wall  scales  off, 
the  inner  layer  splits  open,  allowing  the  minute  dry 
spores  to  escape  as  a  "cloud  of  dust."  These  are 
readily  carried  by  the  wind  until  caught  on  some 
moist  spot  favorable  for  their  growth.  They  are 
found  on  dry,  sandy  soils,  showing  that  very  little 
moisture  is  needed;  but  when  this  is  found,  the 
spore  swells,  germinates,  and  grows  into  a  new 
vegetative  ball,  which  completes  the  cycle. 

Wheat  grains  taken  from  the  wrappings  of  mum- 
mies are  said  to  have  sprouted  when  given  moist- 
ure and  warmth.  Whether  this  be  true  or  not,  there 
can  be  no  doubt  that  the  vitality  of  some  seeds  and 
spores  is  wonderfully  enduring. 

The  spores  of  some  of  the  bacteria  may  be  boiled 
and  many  may  be  frozen^still  life  will  remain. 

Aristotle  declared  that  "all  dry  bodies  become 
damp  and  all  damp  bodies  which  are  dried  engen- 


Vital  Endur- 
ance. 


Dangerous 
Dust. 


76  THE    CHEMISTRY    OF 

der  animal  life."  He  believed  these  dust  germs  to 
be  animalcules  spontaneously  generated  wherever 
the  conditions  were  favorable.  How  could  he,  with- 
out the  microscope,  explain  in  any  other  way  the 
sudden  appearance  of  such  myriads  of  living  forms? 

Now,  it  is  recognized  that  the  air  everywhere 
contains  the  spores  of  molds  and  bacteria,  and  it 
is  this  dust,  carried  in  the  air,  which  falls  in  our 
houses.     This  is  our  enemy. 

A  simple  housemaid  once  said  that  the  sun 
brought  in  the  dust  "atomes"  through  the  window, 
and  the  careful,  old,  New  England  housewife 
thought  the  same.  So,  she  shut  up  the  best  room, 
making  it  dark  and,  therefore,  damp.  Unwittingly, 
she  furnished  to  them  the  most  favorable  conditions 
of  growth,  in  which  they  might  increase  at  the  rate 
of  many  thousands  in  twenty-four  hours. 

"Let  there  be  light"  must  be  the  ever-repeated 
command,  if  we  would  take  the  first  outpost  of  the 
enemy. 

We  live  in  an  invisible  atmosphere  of  dust,  we 
are  constantly  adding  to  this  atmosphere  by  the 
processes  of  our  own  growth  and  waste,  and,  finally, 
we  shall  go  the  way  of  all  the  earth,  contributing 
our  bodies  to  the  making  of  more  dust.  Thus  dust 
has  a  decided  two-fold  aspect  of  friendliness  and 
enmity.  We  have  no  wish  to  guard  ourselves 
against  friends;  so,  for  the  present  purposes,  the 


COOKING    AND    CLEANING.  77 

inimical  action  of  dust,  as  affecting  the  life  and 
health  of  man,  alone  need  challenge  our  attention. 
The  mineral  dust,  animal  waste,  or  vegetable 
debris,  however  irritating  to  our  membranes,  or 
destructive  of  our  clothing,  are  enemies  of  minor 
importance,  compared  with  these  myriads  of  living 
germs,  which  we  feel  not,  hear  not,  see  not,  and 
know  not  until  they  have  done  their  work. 

From  a  sanitary  point  of  view,  the  most  im-  Bacteria, 
portant  of  the  three  living  ingredients  of  dust  is 
that  called  bacteria.  They  are  the  most  numerous, 
the  most  widely  distributed,  and  perhaps  the  small- 
est of  all  living  things.  Their  natural  home  is  the 
soil.  Here  they  are  held  by  moisture,  and  by  the 
gelatinous  character  caused,  in  large  part,  by  their 
own  vital  action.  When  the  surface  of  the  ground 
becomes  dry,  they  are  carried  from  it,  by  the  wind, 
into  the  air.  Rain  and  snow  wash  them  down; 
running  streams  take  them  from  the  soil ;  so  that,  at 
all  times,  the  natural  waters  contain  immense  nitni- 
bers  of  them.  They  are  heavier  than  the  air  and 
settle  from  it  in  an  hour  or  two,  when  it  is  dry  and 
still.  They  are  now  quietly  resting  on  this  page 
which  you  are  reading.  They  are  on  the  floor,  the 
tops  of  doors  and  windows,  the  picture  frames,  in 
every  bit  of  "fluff"  which,  so  adroitly  eludes  the 
broom — in  fact,  everywhere  where  dust  can  lodge. 

The  second  ingredient,  in  point  of  numbers,  is     Molds. 


78  THE    CHEMISTRY    OF 

the  molds.  They,  too,  are  present  in  the  air,  both 
outside  and  inside  of  our  houses;  but  being  much 
lighter  than  the  bacteria,  they  do  not  settle  so 
quickly,  and  are  much  more  readily  carried  into  the 
air  again,  by  a  very  slight  breeze. 

tfeasts.  The  third,  or  wild  yeasts,  are  not  usually  trouble- 

some in  the  air  or  in  the  dust  of  the  house,  where 
ordinary  cleanliness  rules. 

"Dirt-"  To  the  bacteriologist,  then,  everything  is  dirty 

unless  the  conditions  for  germ-growth  have  been 
removed,  and  the  germs,  once  present,  killed. 
All  of  this  dirt  cannot  be  said  to  be  "matter  in  the 
wrong  place,"  only  when  it  is  the  wrong  kind  of 
matter  in  some  particular  place.  The  bacteria  are 
Nature's  scavengers.  Every  tree  that  falls  in  the 
forest — animal  or  vegetable  matter  of  all  kinds  is 
immediately  attacked  by  these  ever-present,  invisi- 
ble agents.  By  their  life-processes,  absorbing,  se- 
creting, growing  and  reproducing,  they  silently 
convert  such  matter  into  various  harmless  sub- 
stances. They  are  faithful  laborers,  earning  an 
honest  living,  taking  their  wages  as  they  go.  Their 
number  and  omnipresence  show  the  great  amount 
of  work  there  must  be  for  them  to  do. 

Then  why  should  we  enter  the  lists  against  such 
opponents?  Because  this  germ-community  is  like 
any  other  typical  community. 

The  majority  of  the  individuals  are  law-abiding, 


COOKING    AND    CLEANING.  19 

respectable  citizens;  yet  in  some  dark  corner  a  thief 
may  hide,  or  a  cut-throat  steal  in  unawares.  If 
this  happens,  property  may  be  destroyed  and  life 
itself  endangered. 

All  of  these  forms  destroy  our  property; 
but  a  certain  few  of  the  bacteria  cause  disease 
and  death.  In  a  very  real  sense,  so  soon  as  an  or- 
ganism begins  to  live  it  begins  to  die ;  but  these  are 
natural  processes  and  do  not  attract  attention  so 
long  as  the  balance  between  the  two  is  preserved. 
When  the  vital  force  is  lessened,  by  whatever  cause, 
disease  eventually  shows  itself.  Methods  for  the 
cure  of  disease  are  as  old  as  disease  itself;  but 
methods  for  the  prevention  of  disease  are  of  late 
birth.  Here  and  there  along  the  past,  some  minds, 
wiser  than  their  age,  have  seen  the  possibilities  of 
such  prevention;  but  superstition  and  ignorance 
have  long  delayed  the  fruition  of  their  hopes. 

"An  ounce  of  prevention  is  worth  a  pound  of  Prevention  «l 
cure,"  though  oft  repeated  has  borne  scanty  fruit 
inj  daily  living.  When  the  cause  of  smallpox, 
tuberculosis,  diphtheria,  typhoid  fever,  and  other 
infectious  diseases  is  known  to  be  a  living  plant, 
which  cannot  live  without  food,  it  seems,  at  first 
sight,  a  simple  matter  to  starve  it  out  of  existence. 
This  has  proved  to  be  no  simple  nor  easy  task;  so 
much  the  more  is  each  person  bound  by  the  law 
of  self-love  and  the  greater  law,  "Thou  shalt  love 


Disease. 


80  THE    CHEMISTRY    OF 

thy  neighbor  as  thyself,"  to  do  his  part  toward 
driving  these  diseases  from  the  world. 

Any  one  of  these  dust-germs  is  harmless  so  long 
as  it  cannot  grow.  Prevent  their  growth  in  the 
human  body,  and  the  diseased  condition  cannot 
occur. 

Prevention,  then,  is  the  watchword  of  modern 
sanitary  science. 

It  may  be  asked:  How  do  the  germs  cause  dis- 
ease? 

Why  do  they  not  always  cause  disease? 

Numerous  answers  have  been  given  during  the 
short  time  the  germ  theory  of  infectious  diseases 
has  been  studied.  If  we  follow  the  history  of  this 
study,  we  may  find,  at  least,  a  partial  answer. 

A  person  is  "attacked"  by  smallpox,  diphtheria, 
lockjaw,  typhoid  fever,  or  some  kindred  disease. 
Common  speech  recognizes  in  the  use  of  the  word 
"attacked"  that  an  enemy  from  outside  has  begun, 
by  force,  a  violent  onset  upon  the  person.  This 
enemy — a  particular  bacterium  or  other  germ,  has 
entered  the  body  in  some  way.  There  may  have 
been  contact  with  another  person  ill  with  the  same 
disease.  The  germ  may  have  entered  through  food 
on  which  it  was  resting,  by  water,  or  by  dust  as 
it  touched  the  exposed  flesh,  where  the  skin  was 
broken  by  a  scratch  or  cut.  It  found  in  the  blood 
or  flesh  the  moisture  and  warmth  necessary  for  its 


COOKING    AND    CLEANING.  81 

growth,  and,  probably,  a  supply  of  food  at  once  de- 
sirable and  bountiful.  It  began  to  feed,  to  grow, 
and  to  multiply  rapidly,  until  the  little  one  became 
a  million.  At  this  stage  the  patient  knew  he  was 
ill.  It  was  thought,  at  first,  that  the  mere  presence 
in  the  body  of  such  enormous  numbers  caused  the 
disease. 

Bacteria  like  the  same  kinds  of  food  which  we     Food  of 

Bacteria* 

lilce.  Though  they  can  and  will  live  on  starvation 
rations,  they  prefer  a  more  luxurious  diet.  This 
fact  led  to  the  idea  that  they  supplied  their  larder 
by  stealing  from  the  food  supply  of  the  invaded 
body;  so  that,  while  the  uninvited  and  unwelcome 
guest  dined  luxuriously,  the  host  sickened  of  starva- 
tion.   This  answer  is  now  rejected. 

The  food  of  the  bacteria  is  not  only  similar  in 
kind  to  our  own  food,  but  it  must  also  undergo  like 
processes  of  solution  and  absorption. 

Solution  is  brought  about  by  the  excretion  of 
certain  substances,  similar  in  character  and  in  ac- 
tion to  the  ferments  secreted  in  the  animal  mouth, 
stomach  and  intestines.  These  excretions  reduce 
the  food  materials  to  liquids,  which  are  then  ab- 
sorbed. 

The  pathogenic  or  disease-producing  germs  are 
found  to  throw  out  during  their  processes  of  as- 
similation and  growth,  various  substances  which 
are  poisons  to  the  animal  body,  as  are  aconite  and 


82 


THE    CHEMISTRY    OF 


digitalis.  These  areabsorbed  and  carried  by  the  blood 
throughout  the  entire  system.  Tliese  poisons  are 
called  toxines.  It  is  now  believed  that  it  is  these 
bacterial  products,  the  toxines  or  poisons,  which 
are  the  immediate  cause  of  the  diseased  condition. 

Inoculation  of  some  of  the  lower  animals  with 
the  poisoned  blood  of  a  diseased  person,  in  which 
blood  no  germ  itself  was  present,  has  repeatedly 
produced  the  identical  disease.  It  is  far  easier  to 
keep  such  manufacturers  out  of  the  body  than  to 
"regulate"  their  manufactures  after  an  entrance  has 
been  gained. 

These  faint  glimpses  into  the  "Philosophy  of 
Cleanness"  lead  to  another  question,  namely:  How 
shall  we  keep  clean? 

The  first  requisite  for  cleanness  is  light — direct 
sunlight  if  possible.  It  not  only  reveals  the  visible 
dirt,  but  allies  itself  with  us  as  an  active  agent 
towards  the  destruction  of  the  invisible  elements  of 
uncleanness.  That  which  costs  little  or  nothing  is 
seldom  appreciated;  so  this  all-abundant,  freely- 
given  light  is  often  shut  out  through  man's  greed 
or  through  mistaken  economy.  The  country  dwell- 
er surrounds  his  house  with  evergreens  or  shade 
trees,  the  city  dweller  is  surrounded  by  high  brick 
walls.  Blinds,  shades,  or  thick  draperies  shut  out 
still  more,  and  prevent  the  beneficent  sunlight  from 
acting  its  role  of  germ-prevention  and  germ-de- 


COOKING    AND    CLEANING.  83 

struction.  Bright-colored  carpets  and  pale-faced 
children  are  the  opposite  results  which  follow. 
"Sunshine  is  the  enemy  of  disease,  which  thrives  in 
darkness  and  shadow."  Consumption  and  scrofu- 
lous diseases  are  well-nigh  inevitable,  when  blinds 
are  tightly  closed  and  trees  surround  the  house, 
causing  darkness,  and,  thereby,  inviting  dampness. 
As  far  as  possible  let  the  exterior  of  the  house  be 
bathed  in  sunlight.  Then  let  it  enter  every  nook  and 
cranny.  It  will  dry  up  the  moisture,  without  which 
the  tiny  disease  germs  or  other  plants  cannot  grow; 
it  will  find  and  rout  them  by  its  chemical  action. 
Its  necessity  and  power  in  moral  cleanness,  who 
can  measure? 

More  plentiful  than  sunlight  is  air.    We  cannot     Pure  Air. 
shut  it  out  entirely  as  we  can  light;  but  there  is 
dirty  air  just  as  truly  as  dirty  clothes  and  dirty 
water.     The  second  requisite  for  cleanness,  then, 
is  pure  air. 

Primitive  conditions  of  human  life  required  no  primitive 
thought  of  the  air  supply,  for  man  lived  in  the  open ;  Life, 
but  civilization  brings  the  need  of  attention  and 
care  for  details;  improvements  in  some  directions 
are  balanced  by  disadvantages  in  others;  luxuries 
crowd  out  necessities,  and  man  pays  the  penalty 
for  his  disregard  of  Nature's  laws.  Sunlight,  pure 
air  and  pure  water  are  our  common  birthright, 
which  we  often  bargain  away  for  so-called  com- 
forts. 


84 


THE    CHEMISTRY    OF 


Air  Pollution. 


Sunlight  is  purity  itself.  Man  cannot  contam- 
inate it,  but  the  air  about  him  is  what  man  makes  it 
Naturally,  air  is  the  great  "disinfectant,  antiseptic 
and  purifier,  and  not  to  be  compared  for  a  moment 
with  any  of  artificial  contrivance,"  but  under  man's 
abuse  it  may  become  a  death-dealing  breath. 

Charlemagne  said:  "Right  action  is  better  than 
knowledge ;  but  to  act  right  one  must  know  right." 
Nature's  supply  of  pure  air  is  sufficient  for  all,  but 
to  have  it  always  in  its  pure  state  requires  knowl- 
edge and  constant,  intelligent  action. 

The  gaseous  products  of  the  combustion  carried 
on  within  our  bodies;  like  products  from  our  arti- 
ficial sources  of  heat  and  light — burning  coal,  gas 
and  oil ;  waste  matters  of  life  and  manufactures  car- 
ried into  the  air  through  fermentation  and  putre- 
faction— all  these,  with  the  innumerable  sources  of 
dust  we  have  already  found,  load  the  air  with  im- 
purities. Some  are  quickly  recognized  by  sight, 
smell  or  taste;  but  many,  and  these  the  more  dan- 
gerous, are  unrecognizable  by  any  sense.  They 
show  their  actions  in  our  weakened,  diseased  and 
useless  bodies.  Dr.  James  Johnson  says:  "All 
the  deaths  resulting  from  fevers  are  but  a  drop  in 
the  ocean,  when  compared  with  the  numbers  who 
perish  from  bad  air." 

The  per  cent  of  pollution  in  the  country  is  much 
smaller  than  in  the  city,  where  a  crowded  popula- 


COOKING    AND    CLEANING.  85 

tion  and  extensive  manufactories  are  constantly 
pouring  forth  impure  matters,  but  by  rapidly  mov- 
ing currents,  even  this  large  per  cent  is  soon  diluted 
and  carried  away.  Would  that  the  air  in  country 
houses,  during  both  winter  and  summer,  might 
show  an  equally  small  per  cent! 

Air  is  a  real  substance.  It  can  be  weighed.  It  Air  a  Sub- 
will  expand,  and  may  be  compressed  like  other 
gases.  It  requires  considerable  force  to  move  it, 
and  this  force  varies  with  the  temperature.  When 
a  bottle  is  full  of  air,  no  more  can  be  poured  in. 
Our  houses  are  full  of  air  all  the  time.  No  more 
can  come  in  till  some  has  gone  out.  In  breathing, 
we  use  up  a  little,  but  it  is  immediately  replaced 
by  expired  air,  which  is  impure.  Were  there  no 
exits  for  this  air,  no  pure  air  could  enter,  and  we 
should  soon  die  of  slow  suffocation.  The  better 
built  the  house  the  quicker  the  suffocation,  unless 
special  provision  be  made  for  a  current  of  fresh  air 
to  push  out  the  bad.  Fortunately  no  house  is  air 
tight.  Air  will  come  in  round  doors  and  windows, 
but  this  is  neither  sufficient  to  drive  out  the  bad 
nor  to  dilute  it  beyond  harm.  Therefore  the  air  of 
all  rooms  must  be  often  and  completely  changed, 
either  by  special  systems  of  ventilation,  or  by  in- 
telligent action  in  the  opening  of  doors  and  win- 
dows. 

Sunlight  and  pure  air  are  the  silent  but  powerful     cleanness 


86  COOKING   AND    CLEANING. 

allies  of  the  housewife  in  her  daily  struggle  toward 
the  ideal  cleanness,  i.  e.,  sanitary  cleanness,  the 
cleanness  of  health.  Without  these  allies  she  may 
spend  her  strength  for  naught,  for  the  plant-life  of 
the  quiet,  dust-laden  air  will  grow  and  multiply  far 
beyond  her  powers  of  destruction.  These  dust- 
plants  or  micro-organisms  grow  rapidly  in  warm 
places  where  there  is  moisture.  Collections  of 
dust  in  cracks  and  corners,  lodged  in  depressions 
of  the  surface,  as  in  seams  and  carvings,  or  held 
by  rough,  absorbent  materials  as  fabrics,  at  all 
times  furnish  the  seed.  All  organic  materials 
furnish  soil  or  food.  Therefore  the  half-dried 
milk-can,  the  partly  cleaned  dripping-pan,  the 
dampened  clothes  in  the  laundry  basket,  the  wet 
dishcloth  and  damp  towel  will  soon  become  a 
flourishing  dust-garden. 

A  dust-garden  suggests  growth;  growth  of 
dust  means  fermentation  with  its  consequent 
chemical  changes.  Fermentation  is  a  process  of 
decomposition  which  may  end  in  putrefaction. 
This  means  economic  waste. 

Civilized  man  requires  so  many  articles  for  his 
convenience  and  comfort  that  the  problem  of 
cleanness  has  grown  to  be  most  complex. 

But  dry  dust  is  not  the  only  enemy.  The 
mixture  of  dust  with  greasy,  sugary  or  smoky 
deposits  makes  the  struggle  twofold. 


CHAPTER  II. 
Dust  Mixtures. 


Grease  and  Dust. 

THE  various  processes  of  housework  give  rise 
to  many  volatile  substances.  These,  the  vapors 
of  water  or  fat,  if  not  carried  out  of  the  house  in 
their  vaporous  state  will  cool  and  settle  upon  all 
exposed  surfaces,  whether  walls,  furniture  or  fab- 
rics. This  thin  film  entangles  and  holds  the  dust, 
clouding  and  soiling,  with  a  layer  more  or  less  visi- 
ble, everything  within  the  house.  Imperfect  ven- 
tilation allows  additional  deposits  from  fires  and 
lights — the  smoky  products  of  incomplete  com- 
bustion. 

Thorough  ventilation  is,  then,  a  preventive  meas- 
ure, which  ensures  a  larger  removal  not  only  of  the 
volatile  matters,  but  also  of  the  dust,  with  its  possi- 
ble disease  germs. 

Dust,  alone,  may  be  removed  from  most  sur- 
faces with  a  damp  or  even  with  a  dry  cloth,  or  from 
fabrics  by  vigorous  shaking  or  brushing;  but, 
usually,  the  greasy  or  sugary  deposits  must  first  be 
broken  up  and,  thus,  the  dust  set  free.  This  must  be 
accomplished  without  harm  to  the  material  upon 


Sources  of 
Dirt. 


Removal  ol 
Dust. 


88 


THE    CHEMISTRY    OF 


Processes  of 
Cleaning. 


Grease-Oils. 


Alkali  Metals. 


which  the  unclean  deposit  rests.  Here  is  a  broad 
field  for  the  application  of  chemical  knowledge. 

Cleaning,  then,  involves  two  processes:  First, 
the  greasy  film  must  be  broken  up,  that  the  en- 
tangled dust  may  be  set  free.  Second,  the  dust 
must  be  removed  by  mechanical  means.  Disinfec- 
tion sometimes  precedes  these  processes,  in  or- 
der that  the  dangerous  dust-plants  may  be  killed 
before  removal. 

To  understand  the  methods  of  dust  removal,  it 
is  necessary  to  consider  the  chemical  character  of 
the  grease  and,  also,  that  of  the  materials  effectual 
in  acting  upon  it. 

Grease  or  fats,  called  oils  when  liquid  at  ordinary 
temperature,  are  chemical  compounds  made  of  dif- 
ferent elements,  but  all  containing  an  ingredient 
known  to  the  chemist  as  a  fatty  acid. 

The  chemist  finds  in  nature  certain  elements 
which,  with  the  fatty  acids,  form  compounds  en- 
tirely different  in  character  from  either  of  the  orig- 
inal ingredients.  These  elements  are  called  the 
alkali  metals  and  the  neutral  compounds  formed  by 
their  union  with  the  acid  of  the  fat  are  familiarly- 
known  to  the  chemist  as  salts. 

The  chemical  group  of  "alkali  metals"  comprises 
six  substances:  Ammonium,  Caesium,  Lithium,  Po- 
tassium, Rubidium  and  Sodium.  Two  of  the  six — 
Caesium  and  Rubidium — were  discovered  by  means 


COOKING    AND    CLEANING.  89 

of  the  spectroscope,  not  many  years  ago,  in  the  min- 
eral waters  of  Durckheim,  and,  probably,  the  total 
amount  for  sale  of  all  the  salts  of  these  two  metalh 
could  be  carried  in  one's  pocket.  A  third  alkali 
metal — Lithium — occurs  in  several  minerals,  and 
its  salts  are  of  frequent  use  in  the  laboratory,  but  it 
is  not  sufficiently  abundant  to  be  of  commercial 
importance.  As  regards  the  three  remaining  alkali 
metals,  the  hydrate  of  Ammonium  (NHJOH,  is 
knov^Ti  as  "Volatile  Alkali,"  the  hydrates  of  Po- 
tassium, KOH,  and  Sodium,  NaOH,  as  "Caustic 
Alkalies."  With  these  three  alkaUes  and  their 
compounds,  and  these  alone,  are  we  concerned 
in  housekeeping.  The  volatile  alkali,  Ammonia,  is 
now  prepared  in  quantity  and  price  such  that  every 
housekeeper  may  become  acquainted  with  its  use. 
It  does  not  often  occur  in  soaps,  but  it  is  valuable 
for  use  in  all  cleansing  operations — the  kitchen, 
the  laundry,  the  bath,  the  washing  of  woolens,  and 
in  other  cases  where  its  property  of  evaporation, 
without  leaving  any  residue  to  attack  the  fabric  or 
to  attract  anything  from  the  air,  is  invaluable.  The 
most  extensive  household  use  of  the  alkalies  is  in 
the  laundry,  under  which  head  they  will  be  more 
specifically  described. 

Some   of  the   fatty  acids  combine  readily  with    Soaps. 
alkalies  to  form  compounds  which  we  call  soaps. 
Others  in  contact  with  the  alkalies  form  emulsions, 


90 


THE    CHEMISTRY    OF 


The  Problem 
of  Cleaning. 


Cleaning  of 

Different 

Materials. 


"  FJnUh  "  of 
Woods. 


so-called,  in  which  the  fatty  globules  are  suspended, 
forming  an  opaque  liquid.  These  emulsions  are 
capable  of  being  indefinitely  diluted  with  clear 
water,  and,  by  this  means,  the  fatty  globules  are  all 
carried  away.  Most  of  the  fats  are  soluble  in  ben- 
zine, ether,  chloroform,  naphtha  or  alcohol. 

If  the  housekeeper's  problem  were  the  simple 
one  of  removing  the  grease  alone,  she  would  solve 
it  by  the  free  use  of  one  of  these  solvents  or  by 
some  of  the  strong  alkalies.  This  is  what  the 
painter  does  when  he  is  called  to  repaint  or  to  re- 
finish;  but  the  housewife  wishes  to  preserve  the 
finish  or  the  fabric  while  she  removes  the  dirt.  She 
must,  then,  choose  those  materials  which  will  dis- 
solve or  unite  with  the  grease  without  injury  to  the 
articles  cleaned. 

The  greasy  film  which  entangles  the  unclean  and 
possibly  dangerous  dust-germs  and  dust-particles 
is  deposited  on  materials  of  widely  different  char- 
acter. These  materials  may  be  roughly  divided 
into  two  classes :  One,  where,  on  account  of  some 
artificial  preparation,  the  uncleanness  does  not 
penetrate  the  material  but  remains  upon  the  sur- 
face, as  on  wood,  metal,  minerals,  leather  and  some 
wall  paper;  the  other,  where  the  grease  and  dust 
settle  among  the  fibres,  as  in  fabrics. 

In  the  interior  of  the  house,  woods  are  seldom 
used  in  their  natural  state.    The  surface  is  covered 


COOKING    AND    CLEANING. 


91 


with  two  or  more  coatings  of  different  substances 
which  add  to  the  wood  durabiHty  or  beauty.  The 
finish  used  is  governed  by  the  character  of  the 
wood,  the  position  and  the  purpose  which  it  serves. 
The  cleaning  processes  should  affect  the  final  coat 
of  finish  alone. 

Soft  woods  are  finished  with  paint,  stain,  oil, 
shellac,  varnish,  or  with  two  or  more  of  these  com- 
bined; hard  woods  with  any  of  these  and,  in  addi- 
tion, encaustics  of  wax,  or  wax  with  turpentine  or 
oil. 

All  these  surfaces,  except  those  finished  with 
wax,  may  be  cleaned  with  a  weak  solution  of  soap 
or  ammonia,  but  the  continued  use  of  any  such 
alkali  will  impair  and  finally  remove  the  polish. 
Waxed  surfaces  are  turned  dark  by  water.  Fin- 
ished surfaces  should  never  be  scoured  nor  cleaned 
with  strong  alkaUes,  like  sal-soda  or  potash  soaps.* 
To  avoid  the  disastrous  effects  of  these  alkalies  the 
solvents  of  grease  may  be  used  or  slight  friction 
applied.     Turpentine  dissolves  paint. 

Kerosene  and  turpentine  are  efficient  solvents  for 
grease  and  a  few  drops  of  these  on  a  soft  cloth  may 
be  used  to  clean  all  polished  surfaces.  The  latter 
cleans  the  more  perfectly  and  evaporates  readily; 
the  former  is  cheaper,  safer,  because  its  vapor  is  not 
so  inflammable  as  that  of  turpentine,  and  it  polishes 
a  little  while  it  cleans;  but  it  evaporates  so  slowly 

*  If  the  finish  has  become  very  greasy,  smoky  or  worn,  it  may  be 
economy  to  use  as  strong  an  alkali  as  sal-soda.  The  washing  and  rinsing 
should  be  as  rapid  as  possible.  Refinishing  may  be  necessary  for  clean 
conditions. 


Solvents  of 
Grease. 


92  THE    CHEMISTRY    OF 

that  the  surface  must  be  rubbed  dry  each  time,  or 
dust  will  be  collected  and  retained.  The  harder  the 
rubbing,  the  higher  the  polish.* 

Outside  of  the  kitchen,  the  woodwork  of  the 
house  seldom  needs  scrubbing.  The  greasy  layer 
is  readily  dissolved  by  weak  alkaline  solutions,  by 
kerosene  or  turpentine,  while  the  imbedded  dust  is 
wiped  away  by  the  cloth.  Polished  surfaces  keep 
clean  longest.  Strong  alkalies  will  eat  through  the 
polish  by  dissolving  the  oil  with  which  the  best 
paints,  stains  or  polishes  are  usually  mixed.  If  the 
finish  be  removed  or  broken  by  deep  scratches,  the 
wood  itself  absorbs  the  grease  and  dust,  and  the 
stain  may  have  to  be  scraped  out. 

Woodwork,  whether  in  floors,  standing  finish  or 
furniture,  from  which  the  dust  is  carefully  wiped 
every  day,  will  not  need  frequent  cleaning.  A 
few  drops  of  kerosene  or  some  clear  oil  rubbed  or 
with  a  second  cloth  will  keep  the  polish  bright  and 
will  protect  the  wood. 

Certain  preparations  of  non-drying  oils  are  now 
in  the  market,  which,  when  applied  to  floors,  serve 
to  hold  the  dust  and  prevent  its  spreading  through 
the  room  and  settling  upon  the  furnishings.  They 
are  useful  in  school-rooms,  stores,  etc.,  where  the 
floor  cannot  be  often  cleaned.  The  dust  and  dirt 
stick  in  the  oil  and,  in  time,  the  whole  must  be 
cleaned  off  and  a  new  coating  applied. 

*  Continued  use  of  kerosene  on  white  paint  tends  to  turn  it  yellow. 


COOKING    AND    CLEANING.  93 

Many  housewives  fear  to  touch  the  piano,  how-  a  cieaa 
ever  clouded  or  milky  the  surface  may  become. 
The  manufacturers  say  that  pianos  should  be 
washed  with  soap  and  water.  Use  tepid  water  with 
a  good  quality  of  hard  soap  and  soft  woolen  or  cot- 
ton-flannel cloths.  Wash  a  small  part  at  a  time, 
rinse  quickly  with  clear  water  that  the  soap  may 
not  remain  long-,  and  wipe  dry  immediately.  Do 
all  quickly.  A  well-oiled  cloth  wiped  over  the  sur- 
face and  hard  rubbing  with  the  hand  or  with  cham- 
ois will  improve  the  appearance.  If  there  are  deep 
scratches  which  go  through  the  polish  to  the  wood, 
first,  cover  them  with  oil  and  allow  it  to  soak  in, 
or  dark  lines  will  appear  where  the  alkali  and 
water  touched  the  natural  wood. 

Painted  surfaces,  especially  if  white,  may  be  Paint. 
cleaned  with  whiting,  applied  with  a  moistened 
woolen  cloth  or  soft  sponge.  Never  let  the 
cloth  be  wet  enough  for  the  water  to  run  or 
stand  in  drops  on  the  surface.  Wipe  "with 
the  grain"  of  the  wood,  rinse  in  clear 
water  with  a  second  soft  cloth  and  wipe 
dry  with  a  third.  All  washed  surfaces  should 
be  wiped  dry,  for  moisture  and  warmth  furnish  the 
favorable  conditions  of  growth  for  all  dust-germs, 
whether  bacteria  or  molds.  Cheese  cloth  may  be 
used  for  all  polished  surfaces,  for  it  does  not 
scratch  and  washes  easily. 


94  THE    CHEMISTRY    OF 

Walls  painted  with  oil  paints  may  be  cleaned 
with  weak  ammonia  water  or  whiting  in  the  same 
manner  as  woodwork;  but  if  they  are  tinted  with 
water  colors,  no  cleaning  can  be  done  to  them,  for 
both  liquids  and  friction  will  loosen  the  coloring 
matter. 

Waii-Paper.  Papered  walls  should  be  wiped  down  with  cheese 

cloth,  with  the  rough  side  of  cotton  flannel,  or  some 
other  soft  cloth.  This  will  effectually  remove  all 
free  dust  Make  a  bag  the  width  of  the  broom  or 
brush  used.  Run  in  drawing  strings.  Draw  the 
bag  over  the  broom,  and  tie  closely  round  the  han- 
dle, just  above  the  broom-corn.  Wipe  the  walls 
down  with  a  light  stroke  and  the  paper  will  not  be 
injured.  An  occasional  thorough  cleansing  will  be 
needed  to  remove  the  greasy  and  smoky  deposits. 
The  use  of  bread  dough  or  crumb  is  not  recom- 
mended, for  organic  matter  may  be  left  upon  the 
wall.  A  large  piece  of  aerated  rubber — the 
"sponge"  rubber  used  by  artists  for  erasing  their 
drawings — may  be  used  eflfectually,  and  will  leave 
no  harmful  deposit.  "Cartridge"  paper  may  be 
scoured  with  fine  emery  or  pumice  powder,  for  the 
color  goes  through.  Other  papers  have  only  a  thin 
layer  of  color. 

Varnished  and  waxed  papers  are  now  made 
which  may  be  wiped  with  a  damp  cloth. 

Leather.  Leather  may  be  wiped  with  a  damp  cloth  or  be 


COOKING    AND    CLEANING.  95 

kept  fresh  by  the  use  of  a  little  kerosene.  An  occa- 
sional dressing  of  some  good  oil,  well  rubbed  in, 
will  keep  it  soft  and  glossy. 

Marble  may  be  scoured  with  fine  sand-soap  or  MaAie. 
powdered  pumice,  or  covered  with  a  paste  of  whit- 
ing, borax  or  pipe-clay,  mixed  with  turpentine, 
ammonia,  alcohol  or  soft  soap.  This  should  be  left 
to  dry.  When  brushed  or  washed  oflf,  the  marble 
will  be  found  clean.  Polish  with  coarse  flannel  or 
a  piece  of  an  old  felt  hat.  Marble  is  carbonate  of 
lime,  and  any  acid,  even  fruit  juices,  will  unite 
with  the  lime,  driving  out  the  carbon  dioxide, 
which  shows  itself  in  efifervescence,  if  the  quantity 
of  acid  be  sufficient.  Acids,  then,  should  not  touch 
marble,  if  it  is  desired  to  keep  the  poHsh  intact. 
An  encaustic  of  wax  and  turpentine  is  sometimes 
applied  to  marbles  to  give  them  a  smooth,  shining 
surface.    These  must  not  be  scoured.* 

Pastes  of  whiting,  pipe-clay,  starch  or  whitewash 
may  be  put  over  ornaments  of  alabaster,  plaster  and 
the  like.  The  paste  absorbs  the  grease  and,  by  rea- 
son of  its  adhesive  character,  removes  the  srrime 
and  dust. 

Most  metals  may  be  washed  without  harm  in  a  Metais. 
hot  alkaline  solution  or  wiped  with  a  little  kerosene. 
Stoves  and  iron  sinks  may  be  scoured  with  the 
coarser  materials  like  ashes,  emery  or  pumice ;  but 
copper,  polished  steel,  or  the  soft  metals,  tin,  silver, 
and  zinc  require  a  fine  powder  that  they  may  not 

*New  marbles  have  a  very  high  polish  which  is  easily  scratched. 
These  should  be  washed,  not  scoured. 


«e  THE    CHEMISTRY    OF 

be  scratched  or  worn  away  too  rapidly.  Metal 
bathtubs  may  be  kept  clean  and  bright  with  whiting 
and  ammonia,  if  rinsed  with  boiling  hot  water  and 
wiped  dry  with  soft  flannel  or  chamois. 

Porcelain.  Porcclain  Or  soapstone  may  be  washed  like  metal 

or  scoured  with  any  fine  material. 

Giaw.  Glass  of  windows,  pictures  and  mirrors  may  be 

cleaned  in  many  ways.  It  may  be  covered  with  a 
whiting  paste  mixed  with  water,  ammonia  or  alco- 
hol. Let  the  paste  remain  till  dry,  when  it  may  be 
rubbed  ofif  with  a  sponge,  woolen  cloth  or  paper. 
Polish  the  glass  by  hard  rubbing  with  news- 
papers or  chamois.  Alcohol  evaporates  more 
quickly  than  water  and  therefore  hastens  the 
process;  but  it  is  expensive  and  should  not  touch 
the  sashes,  as  it  might  turn  the  varnish.  Very  good 
results  are  obtained  with  a  tablespoonful  of  kero- 
sene to  a  quart  of  warm  water.  In  winter,  when 
water  would  freeze,  windows  may  be  wiped  with 
•  clear  kerosene  and  rubbed  dry.  Kerosene  does  not 
remove  fly  specks  readily,  but  will  take  of?  grease 
and  dust.  Fly  specks  may  be  dissolved  in  alcohol 
or  strong  alkali,  or  be  scraped  off  with  some 
dull,  hard  edge,  as  a  cent,  nickel  or  the  back  of 
a  knife. 

Success  in  washing  glass  depends  more  upon 
manipulation  than  materials.  It  is  largely  a  matter 
of  patience  and  polishing.     The  outer  surface  of 


COOKING    AND    CLEANING.  97 

windows  often  becomes  roughened  by  the  dissolv- 
ing action  of  rain  water,  or  milky  and  opaque  by 
action  between  the  sun,  rain  and  the  potash  or  soda 
in  the  glass.  Ordinary  cleaning  will  not  make  such 
windows  clear  and  bright.  The  opaqueness  may 
sometimes  be  removed  by  rubbing  with  vinegar 
or    dilute    muriatic    acid.       Polish    with    whiting. 

Household  fabrics,  whether  carpets,  draperies  Fabrici. 
or  clothing,  collect  large  quantities  of  dust,  which 
no  amount  of  brushing  or  shaking  will  entirely  dis- 
lodge. They  also  absorb  vapors  which  con- 
dense and  hold  the  dust-germs  still  more  firmly 
among  the  fibres.  Here  the  fastness  of  color  and 
strength  of  fibre  must  be  considered,  for  a  certain 
amount  of  soaking  will  be  necessary  in  order  that 
the  cleansing  material  may  penetrate  through  the 
fabric.  In  general,  all  fabrics  should  be  washed 
often  in  an  alkaline  solution.  If  the  colors  will  not 
stand  the  application  of  water,  they  may  be  cleansed 
in  naphtha  or  rubbed  with  absorbents.  The  chem- 
istry of  dyeing  has  made  such  progress  during  the 
last  ten  years  that  fast  colors  are  more  frequently 
found,  even  in  the  cheaper  grades  of  fabrics,  than 
could  be  possible  before  this  time.  It  is  now  more 
a  question  of  weak  fibre  than  of  fleeting  color. 
Heavy  fabrics  may  therefore  be  allowed  to  soak 
for  some  time  in  many  waters,  or  portions  of  naph- 
tha, being  rinsed  carefully  up  and  down  without 


98 


THE    CHEMISTRY    OF 


Inflammable 
Materials. 


Prevention  of 
Dirt. 


rubbing.  All  draperies  or  woolen  materials  should 
be  carefully  beaten  and  brushed  before  any  other 
cleaning  is  attempted.  Wool  fabrics  hold  much  of 
the  dirt  upon  their  hook-like  projections,  and  these 
become  knotted  and  twisted  by  hard  rubbing.  If 
the  fabric  be  too  weak  to  be  lifted  up  and  down  in 
the  liquid  bath,  it  may  be  laid  on  a  sheet,  over  a 
folded  blanket,  and  sponged  on  both  sides  with  the 
soap  or  ammonia  solution  or  with  the  naphtha.  If 
the  colors  are  changed  a  little  by  the  alkalies,  rinse 
the  fabrics  in  vinegar  or  dilute  acetic  acid ;  if  affect- 
ed by  acids,  rinse  in  ammonia  water. 

In  the  use  of  naphtha,  benzine,  turpentine,  etc., 
great  caution  is  necessary.  The  vapor  of  all  these 
substances  is  extremely  inflammable.  They  should 
never  be  used  where  there  is  01^3;  fire  or  light  pres- 
ent, nor  likely  to  be  for  several  hours.  A  bottle 
containing  one  of  them  should  never  be  left  un- 
corked. Whenever  possible,  use  them  out-of- 
doors. 

With  both  dust  and  grease,  prevention  is  easier 
than  removal.  If  the  oily  vapors  of  cooking  and 
the  volatile  products  of  combustion  be  removed 
from  the  kitchen  and  cellar,  and  not  allowed  to  dis- 
sipate themselves  throughout  the  house,  the  greasy 
or  smoky  deposits  will  be  prevented  and  the  re- 
moval of  the  dust-particles  and  dust-plants  will  be- 
come a  more  mechanical  process.     Such  vapors 


COOKING    AND    CLEANING.  9^ 

should  be  removed  by  special  ventilators  or  by  win- 
dows open  at  the  top,  before  they  become  con- 
densed and  thus  deposited  upon  everything  in  the 
house.  Let  in  pure  air,  drive  out  the  impure;  fill 
the  house  with  sunshine  that  it  may  be  dry,  and  the 
problem  of  cleanness  is  largely  solved. 

Economy  of  time,  labor  and  materials  results 
in  removing  dust  and  dust  mixtures,  frequently. 

"One  keep-clean  is  worth  a  dozen  make- 
clean"  is  as  true  now  as  it  was  generations  ago. 
The  sooner  a  wrong  condition  can  be  removed 
the  easier  will  be  its  removal ;  less  time  will  be 
required;  and  much  less  harm  done  to  the 
articles  cleaned. 

The  organic  matter  which  is  present  in  most 
dirt  tends  to  harden  or  to  change  in  other  ways 
and,  therefore,  to  become  removable  with  diffi- 
culty. It  may  undergo  chemical  changes  which 
make  it  indelible. 

In  fabrics  the  fibres  may  even  be  destroyed. 


T' 


CHAPTER  III. 
Stains,  Spots,  Tarnish. 

*HESE  three  classes  include  the  particular  de- 
posits resulting  from  accident,  careless- 
ness, or  the  action  of  special  agents,  as  the 
tarnish  on  metals.  They  are  numerous  in  char- 
acter, occur  on  all  kinds  of  materials  and  their  re- 
moval is  a  problem  which  perplexes  all  women 
and  which  requires  considerable  knowledge  and 
much  patience  to  solve.  A  few  suggestions  may 
help  some  one  who  has  not  yet  found  the  best 
way  for  herself. 

Grease-spots.  Grcasc  sccms  to  be  the  most  common  cause  of 

such  spots.  Small  articles  that  can  be  laundered 
regularly  with  soap  and  water,  give  little  trouble. 
These  will  be  discussed  in  the  following  chapter. 

Absorbents  of  Spots  of  grcasc  on  carpcts,  heavy  materials,  or 

colored  fabrics  of  any  kind  which  cannot  be  con- 
veniently laundered,  may  be  treated  with  absorb- 
ents. Heat  will  assist  in  the  process  by  melting 
the  grease.  Fresh  grease  spots  on  such  fabrics 
may  often  be  removed  most  quickly  by  placing 
over  the  spot  a  piece  of  clean  white  blotting  paper 
or  butcher's  wrapping  paper,  and  pressing  the  spot 
with  a  warm  iron.     It  is  well  to  have  absorbent 


'    COOKING    AND    CLEANING.  101 

paper  or  old  cloth  under  the  spot  as  well.  Heat 
sometimes  changes  certain  blues,  greens  and  reds, 
so  it  is  well  to  work  cautiously  and  hold  the  iron 
a  little  above  the  goods  till  the  effect  can  be  noted. 

French  chalk, — a  variety  of  talc,  or  magnesia, 
may  be  scraped  upon  the  spot  and  allowed  to  re- 
main for  some  time,  or  applied  in  fresh  portions, 
repeatedly.  If  water  can  be  used,  chalk,  fuller's 
earth  or  magnesia  may  be  made  into  a  paste  with 
it  or  with  benzine  and  this  spread  over  the  spot. 
When  dry,  brush  the  powder  off  with  a  soft  brush. 

For  a  fresh  spot  on  fabrics  of  delicate  texture  or 
color,  when  blotting  paper  is  not  at  hand,  a 
visiting  or  other  card  may  be  split  and 
the  rough  inner  siu-face  rubbed  gently  over  the 
spot.  Slight  heat  under  the  spot  may  hasten  the 
absorption.  Powdered  soapstone,  pumice,  whit- 
ing, buckwheat  flour,  bran  or  any  kind  of  coarse 
meal  are  good  absorbents  to  use  on  carpets  or  up- 
holstery. They  should  be  applied  as  soon  as  the 
grease  is  spilled.  Old  spots  will  require  a  solvent 
and  fresh  ones  may  be  treated  in  the  same  way. 

Grease,  as  has  been  said,  may  be  removed   in     Solvents  of 

Grease. 

three  ways,  by  forming  a  solution,  an  emulsion, 
or  a  true  soap.  "yVherever  hot  water  and  soap  can 
be  applied,  the  process  is  one  of  simple  emulsion, 
and  continued  applications  should  remove  both 
the  grease  and  the  entangled    dust;  but  strong 


102  THE    CHEMISTRY    OF 

soaps  ruin  some  colors  and  textures.  Ammonia 
or  borax  may  replace  the  soap,  still  the  water  may- 
affect  the  fabric,  so  the  solvents  of  grease  are  safer 
for  use.  Chloroform,  ether,  alcohol,  turpentine, 
benzine  and  naphtha,  all  dissolve  grease.  In  their 
commercial  state  some  of  these  often  contain  im- 
purities which  leave  a  residue,  forming  a  dark  ring, 
which  is  as  objectionable  as  the  original  grease. 
Turpentine  is  useful  for  coarser  fabrics,  while 
chloroform,  benzine  and  naphtha  are  best  for  silks 
and  woolens.  Ether  or  chloroform  can  usually 
be  applied  to  all  silks,  however  delicate. 
Whenever  these  solvents  are  used,  there 
should  be  placed  under  the  spot  some  absorb- 
ent material,  like  a  thick  pad  of  cloth,  blot- 
ting paper  or  a  layer  of  chalk  to  take  up  the 
excess  of  liquid. 

Then  rub  the  spot  from  the  outside  toward 
the  center  to  prevent  the  spreading  of  the 
liquid,  to  thin  the  edges,  and,  thus,  to  ensure 
rapid  and  complete  evaporation.  The  cleansing 
liquid  should  not  be  left  to  dry  of  itself. 
The  cloth  should  be  rubbed  dry,  but  very 
carefully,  for  the  rubbing  may  remove  the 
nap  from  woolen  goods  and,  therefore,  change 
the  color  or  appearance.  Apply  the  solvent 
with  a  cloth  as  nearly  like  the  fabric  to  be 
cleaned,     in     color    and     texture,     as    possible, 


COOKING   AND    CLEANING.  103 

or,  in  general,  use  a  piece  of  sateen,  which  does 
not  grow  Hnty.  On  thick  goods  a  stiff  brush, 
and  on  thin  goods  a  soft  one,  will  reach  into  the 
meshes.  This  should  be  struck  against  the  cloth 
more  than  rubbed  across  it.  It  is  well  to  apply 
all  cleansing  liquids  and  all  rubbing  on  the  wrong 
side  of  the  fabric.  None  of  these  solvents  can  be 
used  near  a  flame. 

The  troublesome  "dust  spot"  has  usually  a  neg-     "Dust^ 
lected  grease  spot  for  its  foundation.     After  the 
grease  is  dissolved,  the  dust  must  be  cleaned  out 
by  thorough  rinsing  with  fresh  liquid  or  by  brush- 
ing after  the  spot  is  dry. 

Our  grandmothers  found  ox-gall  an  efficient  Ox-gaii. 
cleanser  both  for  the  general  and  special  deposits. 
It  is  as  effectual  now  as  then  and  is  especially  good 
for  carpets  or  heavy  cloths.  It  may  be  used  clear 
for  spots,  or  in  solution  for  general  cleansing  and 
brightening  of  colors.  Its  continued  use  for  car- 
pets does  not  fade  the  colors  as  ammonia  or  salt 
and  water  is  apt  to  do. 

■  Cold  or  warm  grease  on  finished  wood  can  be  "^''^^X"* 
wiped  off  easily  with  a  woolen  cloth  moistened 
in  soapsuds  or  with  a  few  drops  of  turpentine. 
Soap  should  never  be  rubbed  on  the  cloth  except, 
possibly,  for  very  bad  spots  round  the  kitchen 
stove  or  table.  Solutions  of  washing  soda,  potash, 
or  the  friction,  that  may  be  used  safely  on  unfin- 


104  THE    CHEMISTRY    OF 

ished  woods,  will  take  out  the  grease  but  will  also 
destroy  the  polish. 

Hot  grease  usually  destroys  the  polish  and 
sinks  into  the  wood.  It  then  needs  to  be  treated 
like  grease  on  unfinished  wood  or  scraped  out 
with  fine  steel  wool  or  wire  fibre,  sandpaper  or 
emery  paper.  The  color  and  polish  must  then  be 
renewed.  When  hot  grease  is  spilled  on  wood  or 
stone,  if  absorbents  are  not  at  hand,  dash  cold 
water  on  it  immediately.  This  will  solidify  the 
grease  and  prevent  its  sinking  deeply  into  the  ma- 
terial. 

Grease  or  oil  stains  on  painted  walls,  wall-paper 
or  leather,  may  be  covered  with  a  paste  of  pipe- 
clay, or  French  chalk  and  water.  Let  the  paste 
dry  and  after  some  hours  carefully  brush  off  the 
powder.  Sometimes  a  piece  of  blotting  paper  laid 
over  the  spot  and  a  warm  iron  held  against  this, 
will  draw  out  the  grease.  These  pastes  of  absorb- 
ent materials  are  good  for  spots  on  marbles.  They 
may  then  be  mixed  with  turpentine  or  ammonia 
or  soft  soap. 

Paint  is  made  of  oil,  lead  or  zinc  oxide 
and  pigment.  Spots  of  paint,  then,  must  be 
treated  with  something  which  will  take  out  the  oil, 
leaving  the  insoluble  coloring  matter  to  be 
brushed  off.  When  fresh,  such  spots  may 
be    treated    with    turpentine,    benzine    or    naph- 


COOKING  AND    CLEANING.  105 

tha.  For  delicate  colors  or  textures,  chloroform 
or  naphtha  is  the  safest.  The  turpentine,  un- 
less pure,  may  leave  a  resinous  deposit.  This 
may  be  dissolved  in  chloroform  or  benzine,  but 
care  should  be  exercised  in  the  use  of  alcohol 
for  it  dissolves  some  coloring  matters.  Old  paint 
spots  often  need  to  be  softened  by  the  application 
of  grease  or  oil ;  then  the  old  and  the  new  may  be 
removed  together.  Whenever  practicable,  let  all 
spots  soak  a  little,  that  the  necessity  of  hard  rub- 
bing may  be  lessened. 

Paint  on  stone,  bricks  or  marble,  may  be  treated 
with  strong  alkalies  and  scoured  with  pumice 
stone  or  fine  sand. 

Varnish  and  pitch  are  treated  with  the  same     varaish  and 

^  Fitch. 

solvents  as  pamt — turpentme  being  the  one  in 
general  use, — when  the  article  stained  will  not 
bear  strong  alkalies.  Pitch  and  tar  usually  need 
to  be  covered  first  with  grease  or  oil,  to  soften 
them. 

Wax  spots  made  from  candles  should  be  re-  Wax. 
moved  by  scraping  off  as  much  as  possible,  then 
treating  the  remainder  with  kerosene,  benzine, 
ether,  naphtha,  or  with  blotting  paper  and  a  warm 
iron,  as  grease  spots  are  treated.  The  soap  and 
water  of  ordinary  washing  will  remove  slight 
spots.  The  spermaceti  is  often  mixed  with  tallow 
which  makes  a  grease  spot,  and  with  coloring  mat- 
ters which  may  require  alcohol. 


106  TtiE    CHEMISTRY    OF 

Food  Stains.  Spots  made  by  food  substances  are  greasy,  sug- 

ary or  acid  in  their  character,  or  a  combinatioj»  of 
these.  That  which  takes  out  the  grease  will  gen- 
erally remove  the  substance  united  with  it,  as  the 
blood  in  meat  juices.  The  sugary  deposits  are  us- 
ually soluble  in  warm  water.  If  the  acids  from 
fresh  fruits  or  fruit  sauces  aflfect  the  color  of  the 
fabric,  a  little  ammonia  water  may  neutralize  the 
acid  and  bring  back  the  color.  Dilute  alcohol 
may  sometimes  be  used  as  a  solvent  for  colored 
stains  from  fruit.  Blood  requires  cold  or  tepid 
water,  never  hot.  After  the  red  color  is  removed 
soap  and  warm  water  may  be  used. 

Blood  stains  on  thick  cloths  may  be  absorbed 
by  repeated  applications  of  moist  starch. 

Wheel  Wheel-grease  and  lubricants  of  like  nature  are 

'**  ■  mixtures  of  various  oils  and  may  contain  soaps  or 

graphite.  The  ordinary  solvents  of  the  vegetable 
or  animal  oils  will  remove  these  mixtures  from 
colored  fabrics  by  dissolving  the  oil.  The  undis- 
solved coloring  matter  will,  for  the  most  part,  pass 
through  the  fabric  and  may  be  collected  on  thick 
cloth  or  absorbent  paper,  which  should  always  be 
placed  underneath.  From  wash  goods,  it  may  be 
removed,  readily,  by  strong  alkalies  and  water,  es- 
pecially if  softened  first  by  kerosene  or  the  addition 
of  more  grease,  which  increases  the  quantity  of 
soap  made.  Graphite  is  the  most  difficult  of  re- 
moval. 


COOKING   AND    CLEANING.  107 

Ink  spots  are  perhaps  the  worst  that  can  be  en-  ink  stains, 
countered,  because  of  the  great  uncertainty  of  the 
composition  of  the  inks  of  the  present  day.  When 
the  character  of  an  enemy  is  known  it  is  a  compar- 
atively simple  matter  to  choose  the  weapons  to  be 
used  against  him,  but  an  unknown  enemy  must  be 
experimented  upon,  and  conquest  is  uncertain. 
Methods  adapted  to  the  household  are  difficult  to 
find,  as  the  effective  chemicals  need  to  be  applied 
with  considerable  knowledge  of  proportions  and 
effects.  Such  chemicals  are  often  poisons  and, 
in  general,  their  use  by  unskilled  hands  is  not  to 
be  recommended. 

Fresh  ink  will  sometimes  yield  to  clear  cold  oi 
tepid  water.  Skimmed  milk  is  safe  and  often  ef- 
fective. If  the  cloth  is  left  in  till  the  milk  sours, 
the  result  is  at  times  more  satisfactory.  This  has 
proved  effective  on  light  colored  dress  goods 
where  strong  acids  might  have  affected  the  colored 
printed  patterns.  Some  articles  may  have  a  bit  of 
ice  laid  over  the  stain  with  blotting  paper  under 
it  to  absorb  the  ink  solution.  Remove  the  satur- 
ated portions  quickly  and  continue  the  process  till 
the  stain  has  nearly  or  quite  disappeared.  The  last 
slight  stain  may  be  taken  out  with  soap  and  water. 
Some  colored  dress  goods  will  bear  the  applica- 
tion of  hot  tartaric  acid  or  of  muriatic  acid,  a  drop 
at  a  time,  as  on  white  goods. 


108  THE    CHEMISTRY    OF 

Ink  on  carpets,  table  covers,  draperies  or  heavy, 
dark  cloths  of  any  kind,  may  be  treated  immedi- 
ately with  absorbents  to  keep  the  ink  from  spread- 
ing. Bits  of  torn  blotting  paper  may  be  held  at 
the  surface  of  the  spot  to  draw  away  the  ink  on 
their  hairy  fibres.  Cotton-batting  acts  in  the  same 
way.  Meal,  flour,  starch,  sawdust,  baking  soda 
or  other  absorbents  may  be  thrown  upon  the  ink 
and  carefully  brushed  up  when  saturated.  If  much 
is  spilled,  it  may  be  dipped  up  with  a  spoon  or 
knife,  adding  a  little  water  to  replace  that  taken 
up,  until  the  whole  is  washed  out.  Then  dry  the 
spot  with  blotting  paper.  The  cut  surface  of  a 
lemon  may  be  used,  taking  away  the  stained  por- 
tion as  soon  as  blackened.  Usually  it  requires 
hard  rubbing  to  remove  the  last  of  the  stain.  Car- 
pets may  be  rubbed  with  a  floor  brush,  while  a 
soft  toothbrush  may  be  used  for  more  delicate  ar- 
ticles. With  white  goods  a  solution  of  bleaching 
powder  may  be  used,  but  there  is  always  danger 
of  rotting  the  fibres  unless  rinsing  in  ammonia 
water  follow,  in  order  that  the  strong  acid  of  the 
powder  may  be  neutralized. 

Fresh  ink  stains  on  polished  woods  may  be 
wiped  off  with  clear  water,  and  old  stains  of  some 
inks  likewise  yield  to  water  alone.  The  black  col- 
oring matter  of  other  inks  may  be  wiped  off  with 
the  water,  but  a  greenish  stain  may  still  remain 


COOKING  AND   CLEANING. 


109 


which  requires  turpentine.  In  general,  turpentine 
is  the  most  effectual  remover  of  ink  from  polished 
woods. 

The  indelible  inks  formerly  owed  their  perman- 
ence to  silver  nitrate;  now,  many  are  made  from 
aniline  solutions  and  are  scarcely  affected  by  any 
chemicals.  The  silver  nitrate  inks,  even  after  ex- 
posure to  light  and  the  heat  of  the  sun  or  of  a  hot 
flat-iron,  may  be  removed  by  bleaching  liquor. 
The  chlorine  replaces  the  nitric  acid  forming  a 
white  silver  chloride.  This  may  be  dissolved  in 
strong  ammonia  or  a  solution  of  sodium  hyposul- 
phite. Sodium  hyposulphite,  which  may  be 
bought  of  the  druggists,  will  usually  remove  the 
silver  inks  without  the  use  of  bleaching  fluid  and  is 
not  so  harmful  to  the  fibres.  Some  inks  contain 
carbon  which  is  not  affected  by  any  chemicals. 

The  aniline  inks,  if  treated  with  chemicals  may 
spread  over  the  fabric  and  the  last  state  be  worse 
than  the  first.  Other  chemicals  are  effective  with 
certain  inks,  but  some  are  poisonous  in  themselves 
or  in  their  products,  some  injure  the  fabric,  and 
all  require  a  knowledge  of  chemical  reactions  in 
order  to  be  safely  handled.  Dried  ink  stains  on 
silver,  as  the  silver  tops  of  inkstands  may  be 
moistened  with  chloride  of  lime  and  rubbed  hard. 

Polished  marble  may  be  treated  with  turpen- 
tine, "cooking  soda"  or  strong  alkalies,  remem- 


Indelible 
Inks;. 


Aniline  Ink& 


Marble. 


110  THE    CHEMISTRY    OF 

bering  that  acids  should  never  touch  marble  if  it 
is  desired  to  retain  the  polish.  If  the  stain  has 
penetrated  through  the  polish,  a  paste  of  the  alkali 
and  turpentine  may  be  left  upon  the  spot  for  some 
time  and  then  washed  off  with  clear  water. 

Porcelain.  Sometimes  the    porcelain    linings  of  hoppers 

and  bowls  become  discolored  with  yellowish- 
brown  stains  from  the  large  quantities  of  iron  in 
the  water  supply.  These  should  be  taken  oflF  with 
muriatic  acid.  Rinse  in  clean  water  and,  lastly, 
with  a  solution  of  potash  or  soda  to  prevent  any 
injurious  action  of  the  acid  on  the  waste  pipes. 

Alcohol.  Alcohol  dissolves  shellac.    Most  of  the  interior 

woodwork  of  the  house,  whether  finish  or  furni- 
ture, has  been  coated  with  shellac  in  the  process 
of  polishing.  If  then,  any  liquid  containing  alco- 
hol, as  camphor,  perfumes,  or  medicines,  be  spilled 
upon  such  woodwork  and  allowed  to  remain,  a 
white  spot  will  be  made,  or  if  rubbed  while  wet, 
the  dissolved  shellac  will  be  taken  off  and  the  bare 
wood  exposed. 

Heat  Heat  also  turns  varnish  and  shellac  white.    A 

hot  dish  on  the  polished  table  leaves  its  mark. 
These  white  spots  should  be  rubbed  with  oil  till  the 
color  is  restored. 

If  a  little  alcohol  be  brushed  over  the  spot  with 
a  feather,  a  little  of  the  surrounding  shellac  is  dis- 
solved and  spread  over  the  stained  spot.     Hard 


COOKING   AND    CLEANING. 


Ill 


rubbing  with  kerosene  will,  usually,  remove  the 
spot  and  renew  the  polish.  If  the  shellac  be  re- 
moved and  the  wood  exposed  the  process  of  re- 
newal must  be  the  original  one  of  coloring,  shellac- 
ing and  polishing,  until  the  necessary  polish  is  ob- 
tained. 

Caustic  alkalies,  strong  solutions  of  sal-soda, 
potash  and  the  like,  will  eat  off  the  finish.  Apply 
sweet,  olive,  or  other  vegetable  oils,  in  case  of 
such  accidents.  The  continued  use  of  oils  or  al- 
kalies always  darkens  natural  woods. 

The  special  deposits  on  metals  are  caused  by  the 
oxygen  and  moisture  of  the  air,  by  the  presence  of 
other  gases  in  the  house,  or  by  acids  or  corroding 
liquids.  Such  deposits  come  under  the  general 
head  of  tarnish. 

The  metals,  or  their  compounds,  in  common  use 
are  silver,  copper  and  brass,  iron  and  steel,  tin, 
zinc  and  nickel.  Aluminum  is  rapidly  taking  a 
prominent  place  in  the  manufacture  of  household 
utensils. 

There  is  little  trouble  with  the  general  greasy 
film  or  with  the  special  deposits  on  articles  in  daily 
use,  if  they  are  washed  in  hot  water  and  soap, 
rinsed  well  and  wiped  dry  each  time.  Yet  certain 
articles  of  food  act  upon  the  metal  of  tableware 
and  cooking  utensils,  forming  true  chemical  salts. 
The  salts  of  silver  are  usually  dark  colored  and  in- 


Alkalies. 


Chemical 
Compounds. 


Tarnish  on 
Silver. 


112  THE    CHEMISTRY    OP 

soluble  in  water  or  in  any  alkaline  liquid  which  will 
not  also  dissolve  the  silver.  Whether  found  in  the 
products  of  combustion,  in  food,  as  eggs,  in  the 
paper  or  cloth  used  for  wrapping,  in  the  rubber 
band  of  a  fruit  jar,  or  the  rubber  elastic  which  may 
be  near  the  silver,  sulphur  forms  with  silver  a  gray- 
ish black  compound — a  sulphide  of  silver.  All  the 
silver  sulphides  are  insoluble  in  water.  Rub  such 
tarnished  articles,  before  washing,  with  common 
salt.  By  replacement,  silver  chloride,  a  white  chem- 
ical salt,  is  formed,  which  is  soluble  in  ammonia. 
If  the  article  be  not  washed  in  ammonia  it  will  soon 
turn  dark  again.  Most  of  these  metallic  com- 
pounds formed  on  household  utensils  being  insolu- 
ble, friction  must  be  resorted  to. 
Siiverwai«.  The  matron  of  fifty  years  ago  took  care  of  her 

silver  herself  or  closely  superintended  its  clean- 
ing, for  the  articles  were  either  precious  heirlooms 
or  the  valued  gifts  of  friends.  The  silver  of  which 
they  were  made  was  hardened  by  a  certain  propor- 
tion of  copper  and  took  a  polish  of  great  brilliancy 
and  permanence.  The  matron  of  to-day,  who  has 
the  same  kind  of  silver  or  who  takes  the  same  care, 
is  the  exception.  Plated  ware  is  found  in  most 
households.  The  silver  deposited  from  the  battery 
is  only  a  thin  coating  of  the  pure  soft  metal — very 
bright  when  new,  but  easily  scratched,  easily  tar- 
nished, and  never  again  capable  of  taking  a  beauti- 


COOKING  AND    CLEANING.  113 

ful  polish.  The  utensils,  being  of  comparatively 
little  value,  are  left  to  the  table-girl  to  clean.  She, 
naturally,  uses  the  material  w^hich  will  save  her 
labor. 

In  order  to  ascertain  if  there  was  any  foundation     silver 
for  the  prevalent  opinion  that  there  was  mercury  or 
some  equally  dangerous  chemical  in  the  silver  pow- 
ders commonly  sold,  samples  were  purchased  in 
Boston  and  vicinity,  and  in  New  York  and  vicinity. 

Of  the  thirty-eight  different  kinds  examined. 

25  were  dry  powder. 
10    "     partly  liquid.  ' 

3     "     soaps. 

Of  the  twenty-five  powders,  fifteen  were  chalk  or 
precipitated  calcium  carbonate,  with  a  little  color- 
ing matter,  usually  rouge. 

6  were  diatomaceous  earth. 
2      "     fine  sand  entirely. 
2      "     fine  sand  partly. 

Mercury  was  found  in  none.  No  other  injurious 
chemical  was  found  in  any  save  the  "electro-plating 
batter)'  in  a  bott'lt,''  which  contained  potassium 
cyanide,  KCN,  a  deadly  poison;  but  it  was  labeled 
poison,  although  the  label  also  stated  that  "all  salts 
of  silver  are  poison  when  taken  internally."  This 
preparation  does  coptain  silver,  and  does  deposit  a 
thin  coating,  but  it  is  not  a  safe  article  for  use. 


114 


THE    CHEMISTRY    OF 


Silver 
Polishes. 


Whiting. 


Cleaning  of 
Silver  in 
Quantity. 


Of  the  nine  polishes,  partly  liquid,  five  contained 
alcohol  and  ammonia  for  the  liquid  portion;  four, 
alcohol  and  sassafras  extract.  The  solid  portion,  in 
all  cases,  was  chalk,  with,  in  one  case,  the  addition 
of  a  little  jeweler's  rouge. 

The  caution  to  be  observed  in  the  use  of  these 
preparations  is  in  regard  to  the  fineness  of  the  ma- 
terial. A  few  coarse  grains  will  scratch  the  coat- 
ing of  soft  silver.  Precipitated  chalk,  CaCOg,  or 
well-washed  diatomaceous  earth,  SiOg,  seem  to  be 
of  the  most  uniform  fineness. 

We  may  learn  a  lesson  in  this,  as  well  as  in  many 
other  things,  from  the  old-fashioned  housewife. 
She  bought  a  pound  of  whiting  for  twelve  cents, 
sifted  it  through  fine  cloth,  or  floated  off  the  finer 
portion,  and  obtained  twelve  ounces  of  the  same 
material,  for  three  ounces  of  which  the  modern 
matron  pays  twenty-five  or  fifty  cents,  according  to 
the  name  on  the  box. 

The  whiting  may  be  made  into  a  paste  with  am- 
monia or  alcohol,  the  article  coated  with  this  and 
left  till  the  liquid  has  evaporated.  Then  the  pow- 
der should  be  rubbed  off  with  soft  tissue  paper  or 
soft  unbleached  cloth,  and  polished  with  chamois. 

Sometimes  it  is  desirable  to  clean  a  large  quantity 
of  silverware  at  one  time,  but  the  labor  of  scouring 
and  polishing  each  piece  is  considerable.  They 
may  all  be  placed  carefully  in  a  large  kettle — a  clean 


COOKING  AND   CLEANING. 


115 


wash-boiler  is  convenient  for  packing  the  large 
pieces — and  covered  wiH:h  a  strong  solution  of 
washing-soda,  potash  or  borax.  Boil  them  in  this 
for  an  hour  or  less.  Let  them  stand  in  the  liquor 
till  it  is  cold;  then  polish  each  piece  with  a  little 
whiting  and  chamois.  A  good-sized  piece  of  zinc 
boiled  with  the  silverware  will  help  to  clean  away 
any  sulphides  present,  by  replacing  the  silver  in 
them  and  forming  a  white  compound. 

Silver  should  never  be  rubbed  with  nor  wrapped 
in  woolen,  flannel  or  bleached  cloth  of  any  kind, 
for  sulphur  is  commonly  used  in  bleaching  proc- 
esses; nor  should  rubber  in  any  form  be  present 
where  silver  is  kept.  The  unused  silver  may  be 
wrapped  in  soft,  blue-white  or  pink  tissue  paper, 
prepared  without  sulphur,  and  packed  in  un- 
bleached cotton  flannel  cases,  each  piece  separately. 

Silver  jewelry,  where  strong  soap  or  other  alkali 
is  not  sufficient  for  the  cleaning  process,  may  be 
immersed  in  a  paste  of  whiting  and  ammonia,  and 
when  dry,  brushed  carefully  with  a  soft  brush.  If 
there  be  a  doubt  as  to  the  purity  of  the  silver,  re- 
place the  ammonia  by  sweet  oil  or  alcohol.  The 
ammonia  and  whiting  are  also  good  for  gold.  Jew- 
elry cleaned  with  water  may  be  dried  in  boxwood 
sawdust. 

Care  is  necessary  in  the  use  of  ammonia  in  or  on 
"silver"  topped  articles,  as  vinaigrettes.    These  tops 


Protection  ol 
Silverware. 


Silver 
Jewelry. 


Copper  aod 
Silver. 


116 


THE    CHEMISTRY    OF 


are  often  made  of  copper  with  a  thin  layer  of  silver. 
Whenever  the  ammonia  remains  upon  the  copper, 
it  dissolves  it,  forming-  poisonous  copper  salts. 

Brass  and  copper  must  not  be  cleaned  with  am- 
monia unless  due  care  is  taken  that  every  spot  be 
rinsed  and  wiped  perfectly  dry.  Nothing  is  better 
for  these  metals  than  the  rotten-stone  and  oil  of  old- 
time  practice.  These  may  be  mixed  into  a  paste  at 
the  time  of  cleaning  or  be  kept  on  hand  in  quantity. 
Most  of  the  brass  polishes  sold  in  the  market  are 
composed  of  these  two  materials,  with  a  little  alco- 
hol or  turpentine  or  soap,  to  form  an  emulsion  with 
the  oil.  Oxalic  acid  may  be  used  to  clean  these 
metals,  but  it  must  be  rinsed  or  rubbed  oflf  com- 
pletely, or  green  salts  will  be  formed.  Copper  or 
brass  articles  cleaned  with  acids  tarnish  much  more 
quickly  from  the  action  of  moisture  in  the  air  than 
when  cleaned  with  the  oil  and  soft  powder.  Small 
spots  may  be  removed  with  a  bit  of  lemon  juice  and 
hot  watpr.  An  occasional  rubbing  with  kerosene 
helps  to  keep  all  copper  articles  clean  and  bright. 
Indeed,  kerosene  is  useful  on  any  metal,  as  well  as 
on  wood  or  glass. 

The  presence  of  water  always  favors  chemical 
change.  Therefore  iron  and  steel  rapidly  oxidize 
in  damp  air  or  in  the  presence  of  moisture.  All 
metallic  articles  may  be  protected  from  such  action 
by  a  thin  oily  coating.  Iron  and  steel  articles  not  in 
use  may  be  covered  with  a  thin  layer  of  vaseline. 


COOKING   AND    CLEANING. 


117 


Rust  spots  may  be  scoured  off  with  emery  and 
oil,  covered  with  kerosene  or  sweet  oil  for  some 
time  and  then  rubbed  hard,  or  in  obstinate  cases, 
touched  with  muriatic  acid  and  then  with  ammonia, 
to  neutralize  the  acid. 

A  stove  rubbed  daily  with  a  soft  cloth  and  a  few 
drops  of  kerosene  or  sweet  oil  may  be  kept  black 
and  clean,  though  not  polished.  Substances  spilled 
on  such  a  stove  may  be  cleaned  off  with  soap  and 
water  better  than  on  one  kept  black  with  graphite. 

Nickel  is  now  used  in  stove  ornaments,  in  the 
bathroom,  and  in  table  utensils.  It  does  not  oxidize 
or  tarnish  in  the  air  or  with  common  use.  It  can 
be  kept  bright  by  washing  in  hot  soap-suds  and 
rinsing  in  very  hot  water.  It  may  be  rubbed  with 
a  paste  of  whiting  and  lard,  tallow,  alcohol  or  am- 
monia. 

Aluminum  does  not  tarnish  readily,  and  may  be 
rubbed  with  the  whiting  or  with  any  of  the  fine 
materials  used  for  silver.  It  is  darkened  by 
alkalies. 
'  Kitchen  utensils,  with  careful  use,  may  be  kept 
clean  by  soap  and  water  or  a  liberal  use  of  am- 
monia. Fine  sand-soap  must  occasionally  be  used 
when  substances  are  burned  on  or  where  the  tin 
comes  in  contact  with  flame.  Kerosene  is  a  good 
cleaner  for  the  zinc  stove-boards;  vinegar  and 
water,  if  there  is  careful  rinsing  afterward,  or  a 
strong  solution  of  salt  and  water  may  be  used. 


Iron-rust. 


Care  of 
Stoves. 


Nickel. 


Aluminunia 


Kitchen 
Utensils. 


CHAPTER  IV. 
Laundry. 

THE  health  of  the  family  depends  largely  upon 
the  cleansing  operations  which  belong  to  the 
laundry.  Here,  too,  more  largely  perhaps  than  in 
any  other  line  of  cleaning,  will  a  knowledge  of 
chemical  properties  and  reactions  lead  to  econ- 
omy of  time,  strength  and  material. 

The  numerous  stains  and  spots  on  table  linen 
and  white  clothes  are  dealt  with  in  the  laundry, 
and,  also,  all  fabrics  soiled  by  contact  with  the 
body. 

Body  clothes,  bed  linen  and  towels  become 
soiled  not  only  by  the  sweat  and  oily  secretions  of 
the  body,  but  also  with  the  dead  organic  matter 
continually  thrown  oflf  from  its  surface.  Thus  the 
cleansing  of  such  articles  means  the  removal  of 
stains  of  varied  character,  grease  and  dust,  and  all 
traces  of  organic  matter. 

The  two  most  important  agents  in  this  purifica- 
tion are  water  and  soap. 
Water.  Pure  watcr  is    a  chemical    compound  of  two 

gases,  hydrogen  and  oxygen  (HgO).  It  has  great 
solvent  and  absorbent  power,  so  that  in  nature 
pure  water  is  never  found,  though  that  which  falls 


COOKING   AND    CLEANING.  119 

in  sparsely-settled  districts,  at  the  end  of  a  long 
storm,  may  be  approximately  pure.  The  first  fall 
of  any  shower  is  mixed  with  impurities  which  have 
been  washed  from  the  air.  Among  these  may  be 
acids,  ammonia  and  carbon  in  the  form  of  soot 
and  creosote.  It  is  these  impurities  which  cause 
the  almost  indelible  stain  left  when  rain-water 
stands  upon  window-sills  or  other  finished  wood. 

Cistern  water,  while  soft,  is  liable  to  be  colored  water^"'^  ^°** 
from  shingles,  paint  or  moss  on  the  roof.  Spring 
water  and  well  water,  having  percolated  a  greater 
or  less  distance  through  the  ground,  are  filtered, 
clear  waters.  But  they  have  become  mineralized 
to  a  degree  because  of  the  great  solvent  power 
of  water.  All  ground  waters  contain  more  solid 
residue  than  rain  water,  and  are  more  or  less 
hard  when  they  contain  compounds  of  lime  and 
magnesia.  These  form  insoluble  compounds 
with  soap  and  give  curd-like  masses  on  hands 
or  clothes.  They  waste  the  soap,  therefore,  in 
proportion  to  the  amount  present. 

The  soft  waters  of  the  Atlantic  seaboard  use 
up  very  little  soap.  One  pound  of  standard  Cas- 
tile softens  409  gallons  of  water  containing 
twenty  parts  per  million  of  hardening  sub- 
stances ;  one  pound  of  Ivory  soap  softens  196 
gallons  of  the  same  water,  and  one  pound  of 
Gold  Dust  65  gallons. 


120 


THE   CHEMISTRY   OF 


Temporary 
and 

Permanent 
Hardness. 


Soap. 


In  case  of  a  moderately  hard  water,  not  uncom- 
mon in  wells,  giving  200  parts  hardness  per 
million,  one  pound  of  Castile  soap  softens  60 
gallons,  one  pound  of  Ivory  soap  29  gallons,  and 
one  pound  of  Gold  Dust  24  gallons.  Therefore 
the  expense  of  securing  a  soft  water  supply  is 
partly  met  by  a  saving  in  soap. 

Many  hard  waters  may  be  softened  by  boiling. 
The  gaseous  carbon  dioxide  escapes  and  calcium 
carbonate  falls  to  the  bottom  of  the  vessel.  Or 
the  excess  gas  may  be  taken  up  by  lime  water  in 
the  cold.  Such  hardness  is  often  called  tempo- 
rary, because  it  may  be  removed  easily. 

Permanent  hardness  is  given  by  sulphates, 
chlorides,  nitrates  of  calcium,  which  require 
chemical  action  to  remove.  Such  compounds 
are  converted  into  carbonates  by  the  addition  of 
sal-soda,  soda-ash,  sodium  carbonate,  which  gives 
the  precipitate  of  calcium  carbonate  and  the 
soluble  sodium  sulphate.  Tri-sodium  phosphate 
may  be  used  instead  of  the  carbonate,  and 
calcium  phosphate  precipitated. 

In  many  parts  of  the  country  city  supplies  are 
"softened"  by  chemical  treatment. 

Another  important  material  used  in  the  laundry 
is  soap.  "Whether  the  extended  use  of  soap  be 
preceded  or  succeeded  by  an  improvement  in  any 
community — whether  it  be  the  precursor  or  the  re- 


COOKING   AND    CLEANING.  121 

suit  of  a  higher  degree  of  refinement  among  the 
nations  of  the  earth — the  remark  of  Liebig  must 
be  acknowledged  to  be  true,  that  the  quantity  of 
soap  consumed  by  a  nation  would  be  no  inaccur- 
ate measure  whereby  to  estimate  its  wealth  and 
civilization.  Of  two  countries  with  an  equal 
amount  of  population,  the  wealthiest  and  most 
highly  civilized  will  consume  the  greatest  weight 
of  soap.  This  consumption  does  not  subserve  sen- 
sual gratification,  nor  depend  upon  fashion,  but 
upon  the  feeling  of  the  beauty,  comfort  and  wel- 
fare attendant  upon  cleanliness;  and  a  regard  to 
this  feeling  is  coincident  with  wealth  and  civiliza- 
tion."* 

Many  primitive  people  find  a  substitute  for  soap  soap  SubsU. 
in  the  roots,  bark  or  fruit  of  certain  plants.  Nearly 
every  country  is  known  to  produce  such  vegetable 
soaps,  the  quality  which  they  possess  of  forming 
an  emulsion  with  oily  substances  being  due  to  a 
peculiar  vegetable  substance,  known  as  Saponin. 
Many  of  these  saponaceous  barks,  roots  and  fruits 
are  now  used  with  good  results — the  "soap  bark" 
of  the  druggist  being  one  of  the  best  substances 
for  cleansing  dress  goods,  especially  black,  wheth- 
er of  silk  or  wool. 

The    fruit    of    the    soapberry    tree — Papindus 
Saponaria — a  native  of  the  West  Indies,  is  said  to 

•Muspratt's  Chemistry  as  Applied  to  Arts  a?id Manufactures. 


tutes. 


122  THE    CHEMISTRY   OF 

be  capable  of  cleansing  as  much  linen  as  sixty 
times  its  weight  of  soap. 

Wood  ashes  were  probably  used  as  cleansing 
material  long  before  soap  was  made,  as  well  as 
long  after  its  general  use.  Their  properties  and 
value  will  be  considered  later, 

^Sm^I'***'*  Soaps  for  laundry  use  are  chiefly  composed  of 

alkaline  bases,  combined  with  fatty  acids.  Their 
action  is  "gently  but  efficiently  to  dispose  the 
greasy  dirt  of  the  clothes  and  oily  exudations  of 
the  skin  to  miscibility  with,  and  solubility  in  wash 
water,"* 

Oily  matters,  as  we  have  seen,  are  soluble  in  cer- 
tain substances,  as  salt  is  soluble  in  water,  and  can 
be  recovered  in  their  original  form  from  such  solu- 
tions by  simple  evaporation.  Others  in  contact 
with  alkalies,  form  emulsions  in  which  the  sus- 
pended fatty  globules  make  the  liquid  opaque,  as 
in  soapsuds.  The  soap  is  decomposed  by  water, 
the  alkali  set  free  acts  upon  the  oily  matter  on  the 
clothes,  and  unites  with  it,  forming  a  new  soap. 
The  freed  fatty  acid  remains  in  the  water,  causing 
the  "milkiness,"  or  is  deposited  upon  the  clothes. 

"Potash" and  Certain  compounds  of  two  of  the  alkali  metals, 

potassium  and  sodium,  are  capable  of  thus  saponi- 
fying fats  and  forming  the  complex  substances 
known  as  soaps.     For  the  compounds  of  these  al- 

*  Chemistry  applied  to  the  Manufacture  of  Soaps  and  Candles. — Morfit. 


COOKING   AND    CLEANING.  123 

kalies  employed  in  the  manufacture  of  soap,  we 
shall  use  the  popular  tenns  "potash"  and  "soda,"  as 
less  likely  to  cause  confusion  in  our  readers'  minds. 
Potash  makes  soft  soap;  soda  makes  hard  soap. 
Potash  is  derived  from  wood  ashes,  and  in  the 
days  of  our  grandmothers  soft  soap  was  the  uni- 
versal detergent.  Potash  (often  called  pearlash) 
was  cheap  and  abundant.  The  wood  fires  of  every 
household  furnished  a  waste  product  ready  for  its 
extraction.  Aerated  pearlash  (potassium  bicar- 
bonate), under  the  name  of  saleratus,  was  used  for 
bread.  Soda-ash  was,  at  that  time,  obtained  from 
the  ashes  of  seaweed,  and,  of  course,  was  not  com- 
mon inland. 

The  discovery  by  the  French  manufacturer,  Le- 
blanc,  of  a  process  of  making  soda-ash  from  the 
cheap  and  abundant  sodium  chloride,  or  common 
salt,  has  quite  reversed  the  conditions  of  the  use 
of  the  two  alkalies.  Potash  is  now  about  eight 
cents  a  pound,  soda-ash  is  only  three. 

In  1824,  Mr.  James  Muspratt,  of  Liverpool,  first  ^*c,^|?f*"^ 
carried  out  the  Leblanc  process  on  a  large  scale, 
and  he  is  said  to  have  been  compelled  to  give 
away  soda  by  ,he  ton  to  the  soap-boilers,  before 
he  could  convince  them  that  it  was  better  than  the 
ashes  of  kelp,  which  they  were  using  on  a  small 
scale.  The  soap  trade,  as  we  now  know  it,  came 
into  existence  after  the  soap-makers  realized  the 


124  THE    CHEMISTRY    OF 

value  of  the  new  process.  Soda-ash  is  now  the 
cheapest  form  of  alkali,  and  housekeepers  will  do 
well  to  remember  this  fact  when  they  are  tempted 
to  buy  some  new  " ine"  or  "Crystal." 

In  regard  to  the  best  form  in  which  to  use  the 
alkali  for  washing  purposes,  experience  is  the  best 
guide, — that  is,  experience  reinforced  by  judg- 
ment; for  the  number  of  soaps  and  soap  substi- 
tutes in  the  market  is  so  great,  and  the  names  so 
little  indicative  of  their  value,  that  only  general  in- 
formation can  be  given. 

In  the  purchase  of  soap,  it  is  safest  to  choose 
the  make  of  some  well-known  and  long-established 
firm,  of  which  there  are  several  who  have  a  repu- 
tation to  lose,  if  their  products  are  not  good;  and, 
for  an  additional  agent,  stronger  than  soap,  it  is 
better  to  buy  sal-soda  or  soda-ash  (sodium  car- 
bonate) and  use  it  knowingly,  than  to  trust  to  the 
highly-lauded  packages  of  the  grocery. 
The  Use  of  Washing  soda  should  never  be  used  in  the  solid 

Washing  ° 

Soda.  form,  but  should  be  dissolved  in  a  separate  vessel, 

and  the  solution  used  with  judgment.  The  in- 
judicious use  of  the  solid  is  probably  the  cause  of 
the  disfavor  with  which  it  is  often  regarded.  One 
of  the  most  highly  recommended  of  the  scores  of 
"washing  compounds"  formerly  in  the  market, 
doubtless  owed  its  popularity  to  the  following  di- 
rections:    "Put  the  contents  of  the  box  into  one 


COOKING  AND   CLEANING.  126 

quart  of  boiling  water,  stir  well,  and  add  three 
quarts  of  cold  water;  this  will  make  one  gallon. 
For  washing  clothes,  allow  two  cupfuls  of  liquid 
to  a  large  tub  of  water," 

As  the  package  contained  about  a  pound  of 
washing  soda,  this  rule,  which  good  housekeepers 
have  found  so  safe,  means  about  two  ounces  to  a 
large  tub  of  water,  added  before  the  clothes  are 
put  in. 

Ten  pounds  of  washing  soda  can  be  purchased 
of  the  grocer  for  the  price  of  this  one-pound  pack- 
age with  its  high-sounding  name.  Nearly  all  the 
compounds  in  the  market  depend  upon  washing 
soda  for  their  efiEiciency.  Usually  they  contain 
nothing  else.  Sometimes  soap  is  present  and, 
rarely,  borax.  In  one  or  two,  a  compound  of  am- 
monia has  been  found. 

Ammonia  may  be  used  with  soap  or  as  its  sub-  Ammonia 
stitute.  The  ammonia  ordinarily  used  in  the  house- 
hold is  an  impure  article  and  its  continued  use  yel- 
lows bleached  fabrics.  The  pure  ammonia  may  be 
bought  of  druggists  or  of  dealers  in  chemical  sup- 
plies and  diluted  with  two  or  even  four  parts  of 
water.  Borax,  where  the  alkali  is  in  a  milder  form 
than  it  is  in  washing  soda,  is  an  effectual  cleanser, 
disinfectant  and  bleacher.  It  is  more  expensive 
than  soda  or  ammonia,  but  for  delicate  fabrics  and 
for  many  colored  articles  it  is  the  safest  alkali  in 
use. 


126 


THE    CHEMISTRY    OF 


Turpentine. 


Removal  of 
Stains. 


Fruit-Stains. 


Turpentine  also  is  valuable  in  removing  grease. 
A  tablespoonful  to  a  quart  of  warm  water  is  a  sat- 
isfactory way  of  washing  silks  and  other  delicate 
materials.  It  should  never  be  used  in  hot  water, 
for  much  would  be  lost  by  evaporation,  and  in  this 
form  it  is  more  readily  absorbed  by  the  skin,  caus- 
ing irritation  and  discomfort. 

Preparation  for  General  Washing. 

White  goods  are  liable  to  stains  from  a  variety 
of  sources.  Many  of  these  substances  when  acted 
upon  by  the  moisture  of  the  air,  by  dust,  or  al- 
kalies, change  their  character,  becoming  more  or 
less  indelible;  colorless  matters  acquire  color  and 
liquids  become  semi-solid.  All  such  spots  and 
stains  should  be  taken  out  before  the  clothes  are 
put  into  the  general  wash  to  be  treated  with  soap. 

Fruit  stains  are  the  most  frequent  and  possibly 
the  most  indelible,  when  neglected.  These  should 
be  treated  when  fresh. 

The  juices  of  most  fruits  contain  sugar  in  solu- 
tion, and  pectose,  a  mucilaginous  substance  which 
will  form  jelly.  All  such  gummy,  saccharine  mat- 
ters are  dissolved  most  readily  by  boiling  water, 
as  are  mucilage,  gelatine  and  the  like.  To  remove 
them  when  old,  an  acid,  or  in  some  cases,  a 
bleaching  liquid,  like  "chloride  of  lime"  solution  or 
Javelle  water  will  be  needed. 


COOKING    AND    CLEANING.  127 

Stretch  the  stained  part  over  an  earthen  dish  and 
pour  boiling  water  upon  the  stain  until  it  disap- 
pears. How  to  use  the  acid  and  the  Javelle  water 
Avill  be  explained  later  on. 

Wine  stains  should  be  immediately  covered 
with  a  thick  layer  of  salt.  Boiling  milk  is  often 
used  for  taking  out  wine  and  fruit  stains. 

Most  fruit  stains,  especially  those  of  berries,  are  Use  of  sui- 
bleached  readily  by  the  fumes  of  burning  sulphur. 
SOg.  These  fumes  are  irritating  to  the  mucous 
membrane  and  care  should,  therefore,  be  taken 
not  to  inhale  them.  Stand  by  an  open  window 
and  turn  the  head  away.  Make  a  cone  of  stiflf 
paper  or  cardboard  or  devote  a  small  tin  tunnel  to 
this  purpose.  Cut  oflf  the  base  of  the  paper  cone, 
leaving  it  level  and  have  a  small  opening  at  the 
apex.  On  an  old  plate  or  saucer,  place  a  small 
piece  of  sulphur,  set  it  on  fire,  place  over  it  the 
cone  or  tunnel,  and  hold  the  moistened  stain  over 
the  chimney-like  opening.  Have  a  woolen  cloth 
handy  to  put  out  the  sulphur  flame  if  the  piece  is 
larger  than  is  needed.  A  burning  match  sometimes 
furnishes  enough  SOg  for  small  spots.  Do  not  get 
the  burning  sulphur  on  the  skin. 

Medicine  stains  usually  yield  to  alcohol.    Iodine     Medicine, 
dissolves  more  quickly  in  ether  or  chloroform. 

Coffee,  tea  and  cocoa  stain  badly,  the  latter,  if     Tea,  Coffee, 
neglected,  resisting  even  to  the  destruction  of  the 


128  THE    CHEMISTRY    OF 

fabric.  These  all  contain  tannin,  besides  various 
coloring  matters.  These  coloring  matters  are 
"fixed"  by  soap  and  hot  water.  Clear  boiling 
water  will  often  remove  fresh  coffee  and  tea  stains, 
although  it  is  safer  to  sprinkle  the  stain  with  borax 
and  soak  in  cold  water  first.  (A  dredging  box 
filled  with  borax  is  a  great  convenience  in  the  laun- 
dry.) Old  cocoa  and  tea  stains  may  resist  the  bo- 
rax. Extreme  cases  require  extreme  treatment. 
Place  on  such  stains  a  small  piece  of  washing- 
soda  or  "potash."  Tie  it  in  and  boil  the  cloth  for 
half  an  hour.  It  has  already  been  said  that  these 
strong  alkalies  in  their  solid  form  cannot  be  al- 
lowed to  touch  the  fabrics  without  injury.  With 
this  method,  then,  there  must  be  a  choice  between 
the  stain  and  an  injury  to  the  fabric. 
jayeiie  Water.  An  alkaline  solution  of  great  use  and  conven- 

ience is  Javelle  water.  It  will  remove  stains  and 
is  a  general  bleacher.  This  is  composed  of  one 
pound  of  sal-soda  with  one-quarter  pound  of 
"chloride  of  lime"  —  calcium  hypochlorite  —  in  two 
quarts  of  boiling  water.  Let  the  substances  dis- 
solve as  much  as  they  will  and  the  solution  cool  and 
settle.  Pour  off  the  clear  liquid  and  bottle  it  for 
use.  Be  careful  not  to  let  any  of  the  solid  portion 
pass  into  the  bottle.  Use  the  dregs  to  scour  un- 
painted  woodwork,  or  to  cleanse  waste  pipes. 
When  a  spot  is  found  on  a  white  table-cloth, 


COOKING   AND    CLEANING.  129 

place  under  it  an  overturned  plate.  Apply  Javelle 
water  with  a  soft  tooth-brush,  (The  use  of  a  brush 
protects  the  skin  and  nails.)  Rub  gently  till  the 
stain  disappears,  then  rinse  in  clear  water  and 
finally  in  ammonia.  "Chloride  of  lime"  always 
contains  a  powerful  acid,  as  well  as  some  free 
chlorine. 

Blood  stains  require  clear,  cold  or  tepid  water,     Biood. 
for  hot  water  and  soap  render  the  red  coloring 
matter  less  soluble.    When  the  stain  is  brown  and 
nearly  gone,  soap  and  hot  water  may  be  used. 

Meat  juice  on  the  table  linen  is  usually  com- 
bined with  more  or  less  fat.  This  also  yields  most 
readily  to  the  cold  water,  followed  by  soap. 

Stains  made  by  mucus  should  be  washed  in  am- 
monia before  soap  is  added.  When  blood  is  mixed 
with  mucus,  as  in  the  case  of  handkerchiefs,  it 
is  well  to  soak  the  stains  for  some  hours  in  a  solu- 
tion of  salt  and  cold  water — two  tablespoonfuls  to 
a  quart.  Double  the  quantity  of  salt  for  heavier 
or  more  badly  stained  articles.  The  salt  has  a  dis- 
infecting quality,  and  its  use  in  this  way  is  a  wise 
precaution  in  cases  of  catarrh. 

Milk  exposed  to  the  air  becomes  cheesy,  and     MUk. 
hot  water  with  milk  makes  a  substance  difficult  of 
solution.    Milk  stains,  therefore,  should  be  washed 
out  when  fresh  and  in  cold  water. 

Grass  stains  dissolve  in  alcohol.    If  applied  im-     crasi. 


130  THE    CHEMISTRY    OF 

mediately,  ammonia  and  water  will  sometimes 
wash  them  out.  In  some  cases  the  following  meth- 
ods have  proved  successful,  and  their  simplicity 
recommends  them  for  trial  in  cases  where  colors 
might  be  affected  by  alcohol.  Molasses,  or  a  paste 
of  soap  and  cooking  soda,  may  be  spread  over  the 
stain  and  left  for  some  hours,  or  the  stain  may  be 
kept  moist  in  the  sunshine  until  the  green  color 
has  changed  to  brown,  then  it  will  wash  out  in 
clear  water. 

Mildew  causes  a  spot  of  a  totally  different  char- 
acter from  any  we  have  considered.  It  is  a  true 
mold,  and  like  all  plants  requires  warmth  and 
moisture  for  its  growth.  When  this  necessary 
moisture  is  furnished  by  any  cloth  in  a  warm 
place,  the  mildew  grows  upon  the  fibres.  During 
the  first  stages  of  its  growth,  the  mold  may  be 
removed,  but  in  time  it  destroys  the  fibres. 

Strong  soapsuds,  a  layer  of  soft  soap  and  pulver- 
ized chalk,  or  one  of  chalk  and  salt,  are  all  effec- 
tive if,  in  addition,  the  moistened  cloth  be  sub- 
jected to  strong  sunlight,  which  kills  the  plant 
and  bleaches  the  fibres.  Bleaching  powder  or 
Javelle  water  may  be  tried  in  cases  of  advanced 
growth,  but  success  cannot  be  assured. 

Some  of  the  animal  and  vegetable  oils  may  be 
taken  out  by  soap  and  cold  water  or  dissolved  in 
naphtha,  chloroform,  ether,  etc. 


COOKING   AND    CLEANING.  131 

Some  of  the  vegetable  oils  are  only  sparingly 
soluble  in  cold,  but  readily  soluble  in  hot  alcohol. 
The  boiling  point  of  alcohol  is  so  low  that  care 
should  be  taken  that  the  temperature  be  not  raised 
to  the  ignition  point 

Mineral  oil  stains  are  not  soluble  in  any  alkaline 
or  acid  solutions.  Kerosene  will  evaporate  in  time. 
Vaseline  stains  should  be  soaked  in  kerosene  be- 
fore water  and  soap  touch  them. 

Ink  spots  on  white  goods  are  the  same  in  charac-  ink. 
ter  as  on  colored  fabrics.  Many  of  the  present  inks 
are  made  from  aniline  or  allied  substances  instead 
of  the  iron  compounds  of  the  past.  Aniline  black 
is  indelible ;  the  colored  anilines  may  be  dissolved  in 
alcohol.  Where  the  ink  is  an  iron  compound  the 
stain  may  be  treated  with  oxalic,  muriatic  or  hot 
tartaric  acids,  applied  in  the  same  manner  as  for 
iron-rust  stains.  No  definite  rule  can  be  given,  for 
some  inks  are  affected  by  strong  alkalies,  others  by 
acids,  while  some  wnll  dissolve  in  clear  water. 

The  present  dyes  are  so  much  more  stable  than 
those  of  twenty-five  years  ago,  that  pure  lemon 
juice  or  a  weak  acid  like  hydrochloric,  has  no  effect 
upon  many  colors.  Any  acid  should,  however,  be 
applied  with  caution.  If  the  color  is  affected  by 
acids,  it  may  often  be  restored  by  dilute  ammonia. 

The  red  iron-rust  spots  must  be  treated  with  acid.     ^^^  iron- 
These  are  the  result  of  true  oxidation — the  union 


rust. 


132  THE   CHEMISTRY    OF 

of  the  oxygen  of  the  air  with  the  iron  in  the  pres- 
ence of  moisture.  The  salt  formed  is  deposited 
upon  the  fabric  which  furnishes  the  moisture.  Or- 
dinary "tin"  utensils  are  made  from  iron  coated 
with  tin,  which  soon  wears  oflf,  so  no  moist  fabric 
should  be  left  long  in  tin  unless  the  surface  is  entire. 

Iron-rust  is,  then,  an  oxide  of  iron.  The  oxides 
of  iron,  copper,  tin,  etc,  are  insoluble.  The  chlor- 
ides, however,  are  soluble.  Replace  the  oxygen 
with  the  chlorine  of  hydrochloric  acid  and  the  iron 
compound  will  be  dissolved.  The  method  of  apply- 
ing the  acid  is  very  simple. 

Fill  an  earthen  dish  two  thirds  full  of  hot  water 
and  stretch  the  stained  cloth  over  this.  Have  near 
two  other  dishes  with  clear  water  in  one  and  am- 
monia water  in  the  other.  The  steam  from  the  hot 
water  will  furnish  the  heat  and  moisture  favorable 
for  chemical  action.  Drop  a  little  hydrochloric 
(muriatic)  acid,  HCl,  on  the  stain  with  a  medicine 
dropper.  Let  it  act  a  moment,  then  lower  the  cloth 
into  the  clear  water.  Repeat  till  the  stain  disap- 
pears. Rinse  carefully  in  the  clear  water  and, 
finally,  immerse  in  the  ammonia  water  that  any  ex- 
cess of  acid  may  be  neutralized  and  the  fabric  pro- 
tected. 

Salt  and  lemon  juice  are  often  sufficient  for  a 
slight  stain,  probably  because  a  little  hydrochloric 
acid  is  formed  from  their  union. 


COOKING    AND    CLEANING.  133 

Many  spots  appear  upon  white  goods  which  re-  Bluing, 
semble  those  made  by  iron-rust,  or  the  fabrics 
themselves  acquire  a  general  yellowish  tinge.  This 
is  the  result  of  the  use  of  bluing  and  soap,  where 
there  has  been  imperfect  rinsing  of  the  clothes. 
The  old-time  bluing  was  pure  indigo.  This  is  in- 
sohible,  but,  by  its  use,  a  fine  blue  powder  was 
spread  among  the  fibres  of  the  cloth.  It  required 
careful  manipulation,  which  it  usually  had.  Indigo 
with  sulphuric  acid  can  be  made  to  yield  a  soluble 
paste.  This  is  the  best  form  of  bluing  which  can 
be  used,  for  a  very  little  gives  a  dark,  clear  blue  to 
water,  and  overcomes  the  yellowish  tinge  which 
cotton  or  linen  will  acquire  in  time  unless  well 
bleached  by  sunshine.  The  expense  and  difficulty 
of  obtaining  this  soluble  indigo  has  led  to  the  sub- 
stitution of  numerous  solid  and  liquid  "blues"  by 
the  use  of  which  the  laundress  is  promised  success 
with  little  labor.  Most  of  these  liquid  bluings  con- 
tain some  iron  compound.  This,  when  in  contact 
with  a  strong  alkali,  is  broken  up  and  the  iron  is 
precipitated.  If,  then,  bluing  be  used  where  all  the 
soap  or  alkali  has  not  been  rinsed  from  the  clothes, 
this  decomposition  and  precipitation  takes  place, 
and  a  deposit  of  iron  oxide  is  left  on  the  cloth.  This 
must  be  dissolved  by  acid  like  any  iron-rust. 

Some  "blues"  are  compounds  of  ultramarine,  a 
brilliant  blue  silicate  of  aluminum.    These  are  gen- 


134  THE    CHEMISTRY    OF 

erally  used  in  the  form  of  a  powder  which  is  insol- 
uble, settles  quickly  and,  thereby,  leaves  blue  spots 
or  streaks.  It  is  very  difficult  to  prevent  these  when 
insoluble  powdered  "blues"  are  used.  This  silicate 
combined  with  hydrochloric  acid  forms  a  jelly-like 
mass  from  which  a  white  precipitate  is  formed. 
These  ultramarine  blues  are  sometimes  recom- 
mended because  of  this  white  precipitate,  obviating, 
as  is  said,  the  yellowish  results  of  careless  rinsing, 
inevitable  when  iron  "blues"  are  used.  The  advice 
is  misleading,  for  no  precipitate  is  formed  unless  an 
acid  be  added. 

When  solid  bluing  is  used  it  should  be  placed  in 
a  flannel  bag  and  stirred  about  in  a  basin  of  hot 
water.  In  this  way  only  the  finest  of  the  powder  is 
obtained.  After  this  blued  water  is  poured  into  the 
tub,  it  must  be  continually  stirred,  to  prevent  the 
powder  from  settling  in  spots  or  streaks  upon  the 
clothes. 

First,  then,  the  removal  of  all  dirt,  and  second, 
the  removal,  by  thorough  rinsing,  of  all  soap  or 
other  alkalies  used  in  the  first  process,  and  third, 
long  exposure  to  air  and  sunshine  should  render 
the  use  of  bluing  unnecessary.  The  experience  of 
many  shows  that  clothes  that  have  never  been 
blued,  never  need  bluing.  In  cities  where  conveni- 
ences for  drying  and  bleaching  in  the  sunshine  are 
few,  and  where  clear  water  or  clear  air  are  often  un- 


COOKING   AND    CLEANING.  135 

attainable,  a  thorough  bleaching-  two  or  three  times 
a  year  is  a  necessity ;  but  in  the  country  it  is  wiser  to 
abolish  all  use  of  bluing  and  let  the  great  bleacher, 
the  sun,  in  its  action  with  moisture  and  the  oxygen 
of  the  air,  keep  the  clothes  white  as  well  as  pure. 

Freezing  aids  in  bleaching,  for  it  retains  the 
moisture,  upon  which  the  sun  can  act  so  much  the 
longer.  The  easiest  household  method  of  bleach- 
ing where  clean  grass,  dew  and  sunshine  are  not 
available,  is  by  the  use  of  "bleaching  powder."  In 
the  presence  of  water  and  weak  acids,  even  carbonic 
acid,  oxygen  and  chlorine  are  both  set  free  from 
the  compound.  At  the  moment  of  liberation  the 
action  is  very  powerful.  The  organic  coloring  mat- 
ters present  are  seized  upon  and  destroyed,  thereby 
bleaching  the  fabric. 

Directions  for  the  use  of  the  powder  usually  ac- 
company the  can  in  which  it  is  bought.  The  woman 
who  knows  that  the  acid  always  present  in  the  pow- 
der must  be  completely  rinsed  out  or  neutralized 
by  an  alkali,  may  use  her  bleaching  powder  with 
safety  and  satisfaction. 

All  special  deposits  should  be  removed  before  General 
the  general  cleansing  of  the  fabric  is  undertaken. 
Grease  and  other  organic  matters  are  the  undesir- 
able substances  which  are  to  be  disposed  of  in  the 
general  cleansing.  Grease  alone  is  more  quickly 
acted  upon  by  hot  water  than  by  cold,  but  other 


Cleansing 


136 


THE   CHEMISTRY    OF 


Soaking. 


Boiling. 


'  Yellowness." 


organic  matter  Is  fixed  by  the  hot  water.  There- 
fore, while  hot  water  melts  the  grease  quickly,  the 
mixture  may  be  thus  spread  over  the  surface  and 
may  not  be  removed  by  the  soap. 

An  effective  method,  proved  by  many  housewives 
of  long  experience,  is  to  soap  thoroughly  the  dirti- 
est portions  of  the  clothes,  fold  these  together 
toward  the  center,  roll  the  whole  tightly,  and  soak 
in  cold  water.  The  water  should  just  cover  the 
articles.  In  this  way  the  soap  is  kept  where  it  is 
most  needed,  and  not  washed  away  before  it  has 
done  its  work.  When  the  clothes  are  unrolled  the 
dirt  may  be  washed  out  with  less  rubbing. 

Too  long  soaking  when  a  strong  soap  is  used, 
which  has  much  free  alkali,  would  weaken  the  fab- 
ric. Judgment,  trained  by  experience  must  guide 
in  such  cases,  so  that  effective  cleaning  depends 
upon  careful  manipulation. 

Whether  to  boil  or  not  to  boil  the  clothes  de- 
pends largely  upon  the  purity  of  the  materials  used 
and  the  degree  of  care  exercised.  Many  persons 
feel  that  the  additional  disinfection  which  boiling 
ensures  is  an  element  of  cleanness  not  to  be  disre- 
garded ;  others  think  it  unnecessary  under  ordinary 
conditions,  while  others  insist  that  boiling  yellows 
the  clothes. 

The  causes  of  this  yellowness  seem  to  be:     - 


COOKING   AND    CLEANING. 


137 


Impure  materials  in  the  soap  used ; 

The  deposition,  after  a  time,  of  iron  from  the 
water  or  the  boiler; 

The  imperfect  washing  of  the  clothes — that  is, 
the  organic  matter  is  not  thoroughly  removed. 

The  safest  process  seems  to  be  to  put  the  clothes 
into  cold  water  with  little  or  no  soap,  let  the  tem- 
perature rise  gradually  to  the  boiling  point  and 
remain  there  a  few  minutes. 

Soap  is  more  readily  dissolved  by  hot  water  than 
by  cold,  hence  the  boiling  should  help  in  the  com- 
plete removal  of  the  soap  and  may  well  precede  the 
rinsing. 

Borax — ^A  tablespoonful  to  every  gallon  of 
water — added  to  each  boilerful  serves  as  a  bleacher 
and  an  aid  in  disinfection.  The  addition  of  the 
borax  to  the  last  rinsing  water  is  preferred  by 
many.  In  this  case,  the  clothes  should  be  hung  out 
quite  wet,  so  that  the  bleaching  may  be  thorough. 

"Scalding,"  or  the  pouring  of  boiling  water  over 
the  clothes  is  not  so  effectual  for  their  disinfec- 
tion as  boiling,  because  the  temperature  is  so 
quickly  lowered. 

The  main  points  in  laundry  cleansing  seem  to 
be:— 

The  removal  of  all  stains; 

Soft  water  and  a  good  quality  of  soap; 

The  use  of  strong  alkalies  in  solution  only; 


Scalding, 


Necessities 
for  Good 
Cleansing. 


138 


THE    CHEMISTRY    OF 


Structure  of 
Fibres. 


Cotton 


Wool. 


Linen. 


Not  too  hot  nor  too  much  water  while  the  soap 
is  acting  upon  the  dirt ;  much  water  to  wash  in ; 

Thorough  rinsing,  that  all  alkali  may  be  re- 
moved; and  that  no  dirty  water  remain: 

Long  exposure  to  sunlight — ^the  great  bleacher 
and  disinfectant 

The  fibres  of  cotton,  silk  and  wool  vary  greatly 
in  their  structure,  and  a  knowledge  of  this  struc- 
ture, as  shown  under  the  microscope,  may  guide 
to  proper  methods  of  treatment. 

The  fibres  of  cotton,  though  tubular,  become 
much  flattened  during  the  process  of  manufacture, 
and  under  the  microscope  show  a  characteristic 
twist,  with  the  ends  gradually  tapering  to  a  point. 
It  is  this  twist  which  makes  them  capable  of  being 
made  into  a  firm,  hard  thread. 

The  wool  fibre,  like  human  hair,  is  marked  by 
transverse  divisions,  and  these  divisions  are  ser- 
rated. These  teeth  become  curled,  knotted  or 
tangled  together  by  rubbing,  by  very  hot  water,  or 
by  strong  alkalies.  This  causes  the  shrinking  which 
should  be  prevented.  When  the  two  fibres  are 
mixed  there  is  less  opportunity  for  the  little  teeth 
to  become  entangled  and,  therefore,  there  is  less 
shrinkage. 

Linen  fabrics  are  much  like  cotton,  with  slight 
notches  or  joints  along  the  walls.  These  notches 
serve  to  hold  the  fibres  closely  together  and  enable 


COOKING   AND    CLEANING.  139 

them  to  be  felted  to  form  paper.  Linen,  then,  will 
shrink,  though  not  so  much  as  wool,  for  the  fibres 
are  more  wiry  and  the  teeth  much  shorter. 

Silk  fibres    are    perfectly    smooth,    and    when     suk. 
rubbed,  simply  slide  over  each  other.     This  pro- 
duces a  slight  shrinkage  in  the  width  of  woven 
fabrics. 

All  wool  goods,  then,  require  the  greatest  care     washing  oi 
in  washing.  The  different  waters  used  should  be  of 
the  same  temperature,  and  never  too  hot  to  be 
borne  comfortably  by  the  hand. 

The  soap  used  should  be  in  the  form  of  a  thin 
soap  solution.  No  soap  should  be  rubbed  on  the 
fabric,  and  only  a  good  white  soap,  free  from  rosin, 
or  a  soft  potash  soap,  is  allowable.  Make  each 
water  slightly  soapy  and  leave  a  very  little  in  the 
fabric  at  the  end,  to  furnish  a  dressing  as  nearly 
like  the  original  as  possible. 

Many  persons  prefer  ammonia  or  borax  in  place 
of  the  soap.  For  pure  white  flannel,  borax  gives  the 
best  satisfaction,  on  account  of  its  bleaching  qual- 
ity. Whatever  alkali  is  chosen,  care  should  be  ex- 
ercised in  the  quantity  taken.  Only  enough  should 
be  used  to  make  the  water  very  soft. 

The  fibres  of  wool  collect  much  dust  upon  their 
tooth-like  projections,  and  this  should  be  thor- 
oughly brushed  or  shaken  off  before  the  fabric 
is  put  into  the  water.    All  friction  should  be  by 


140 


THE    CHEMISTRY    OF 


Very  Dirty 
Articles. 


squeezing,  not  by  rubbing.  Wool  should  not  be 
wrung  by  hand.  Either  run  the  fabric  smoothly 
through  a  wringer  or  squeeze  the  water  out,  that 
the  fibres  may  not  be  twisted.  Wool  may  be  well 
dried  by  rolling  the  article  tightly  in  a  thick  dry 
towel  or  sheet  and  squeezing  the  whole  till  all 
moisture  is  absorbed.  Wool  should  not  be  allowed 
to  freeze,  for  the  teeth  will  become  knotted  and 
hard. 

Linen,  like  wool,  collects  much  dirt  upon  the 
surface  which  does  not  penetrate  the  fabric.  Shake 
this  off  and  rub  the  cloth  as  little  as  possible. 
Linen  or  woolen  articles  should  not  be  twisted  in 
the  drying  process,  as  it  is  sometimes  impossible 
to  straighten  the  fibres  afterward. 

Colored  cottons  should  have  their  colors  fixed 
before  washing.  Salt  will  set  most  colors,  but  the 
process  must  be  repeated  at  each  washing.  Alum 
sets  the  colors  permanently,  and  at  the  same  time 
renders  the  fabric  less  combustible,  if  used  in 
strong  solution  after  the  final  rinsing. 

Dish  cloths  and  dish  towels  must  be  kept  clean 
as  a  matter  of  health,  as  well  as  a  necessity  for 
clean,  bright  tableware.  The  greasy  dish  cloth 
furnishes  a  most  favorable  field  for  the  growth 
of  germs.  It  must  be  washed  with  soap  and  hot 
water  and  dried  thoroughly  each  time.  All  such 
cloths   should   also   form   a   part   of  the   weekly 


COOKING  AND   CLEANING. 


141 


wash  and  be  subjected  to  all  the  disinfection  pos- 
sible, with  soap,  hot  water  and  long  drying  in  sun- 
shine and  the  open  air.  Beware  of  the  disease- 
breeding,  greasy  and  damp  dish  cloth  hung  in  a 
warm,  dark  place ! 

Oven  towels,  soiled  with  soot  and  crock,  may  be 
soaked  over  night,  or  for  some  hours,  in  just  kero- 
sene enough  to  cover,  then  washed  in  cold  water 
and  soap. 

With  very  dirty  clothes  or  for  spots,  where  hard 
rubbing  is  necessary,  much  strength  may  be  saved 
by  using  a  scrubbing  brush. 

Laundry  tubs  should  be  carefully  washed  and 
dried.  Wooden  tubs,  if  kept  in  a  very  dry  place, 
and  turned  upside  down,  may  have  the  bottoms 
covered  with  a  little  water. 

The  rubber  rollers  of  the  wringer  may  be  kept 
white  by  rubbing  them  with  a  clean  cloth  and  a 
few  drops  of  kerosene. 

All  waste  and  overflow  pipes,  from  that  of  the 
kitchen  sink  to  that  of  the  refrigerator,  become 
foul  with  grease,  lint,  dust,  and  other  organic  mat- 
ters that  are  the  result  of  bacterial  action.  They 
are  sources  of  contamination  to  the  air  of  the  en- 
tire house  and  to  the  food  supply,  thereby  endan- 
gering health.  All  bath,  set-bowl  and  watei  closet 
pipes  should  be  flushed  generously  once  a  day,  at 
least,     the  kitchen  sink  pipe  with  clear  boiling 


Care  of 
Plumbing. 


142  THE    CHEMISTRY    OF 

water;  and  once  a  week  all  pipes  should  have  a 
thorough  cleaning  with  a  strong  boiling  solution 
of  washing-soda  and  a  monthly  flushing  with  caus- 
tic potash.  The  plumbers  recommend  the  "stone" 
or  crude  potash  for  the  kitchen  pipe.  This  is 
against  their  own  interests,  for  many  a  plumber's 
bill  is  saved  where  the  housewife  knows  the  dan- 
ger and  the  means  of  prevention  of  a  grease-coated 
sink  drain.  The  pipe  of  the  refrigerator  should  be 
cleared  throughout  its  entire  length  with  the  soda 
solution.  Avoid  any  injury  to  the  metallic  rims  of 
the  waste  pipes  by  using  a  large  tunnel. 

Old-fashioned  styles  of  overflow  pipes  retain  a 
large  amount  of  filth,  and  it  is  very  difficult  to  dis- 
lodge it.  A  common  syringe  may  be  devoted  to 
this  purpose.  By  its  patient,  frequent  use  even  this 
tortuous  pipe  may  be  kept  clean. 

Ideal  Cleanness. 
Sanitary  Ideal  clcanncss  requires  the  cleanness  of  the  in- 

Cleanness.  _    _  ^        _ 

dividual,  of  his  possessions,  and  of  his  environ- 
ment. Each  individual  is  directly  responsible  for 
his  personal  cleanness  and  that  of  his  possessions; 
but  over  a  large  part  of  his  environment  he  has 
only  indirect  control.  Not  until  direct  personal 
responsibility  is  felt  in  its  fullest  sense,  and  exer- 
cised in  all  directions  toward  the  formation  and 
carrying  out  of  sufficient  pubHc  laws,  will  sanitary 


COOKING   AND    CLEANING. 


143 


cleanness  supplant  the  cure  of  a  large  number  of 
diseases  by  their  prevention. 

Many  of  the  diseases  of  childhood  are  directly 
traceable  to  uncleanness,  somewhere.  By  these  dis- 
eases the  system  is  often  so  weakened  that  others 
of  different  character  are  caused  which,  though 
slow  in  action,  may  baffle  all  science  in  their  cure. 

The  necessity  of  forming  systematic  habits  of 
cleanness  in  the  young  is  the  first  step  toward  sani- 
tary health.  They  should,  then,  step  by  step,  as 
they  are  able  to  grasp  the  reasons  for  the  habits, 
be  educated  in  all  the  sciences  which  give  them 
the  knowledge  of  the  cause  and  eflfects  of  un- 
cleanness, the  methods  of  prevention  and  removal, 
and  the  relation  of  all  these  to  building  laws  and 
municipal  regulations. 

The  first  environment  to  be  kept  clean  is  the 
home.  But  personal  cleanness  and  household 
cleanness  should  not  be  rendered  partially  futile  by 
unclean  schoolhouses,  public  buildings  and  streets. 

The  housekeeping  of  the  schoolhouses,  especially, 
should  be  carried  on  with  a  high  regard  to  all 
hygienic  details,  since  here  the  degree  of  danger 
is  even  greater  than  in  the  home.  In  public 
schoolhouses  the  conditions  favorable  to  the  pres- 
ence of  disease  germs  abound.  If  present,  their 
growth  is  rapid,  and  the  extent  of  contagion  be- 
yond calculation.    The  cooperation  of  all  most  in- 


Personal 
Cleanness. 


144  COOKING   AND    CLEANING. 

terested — pupils  and  teachers — should  be  expected 
and  required  as  firmly  as  their  cooperation  in  any 
other  department  of  education. 
Ms^''*^  ^***°'  '^^^  sanitary  condition  of  every  school  building 

should  be  a  model  object  lesson  for  the  home;  then, 
instruction  in  personal  cleanness  will  carry  the 
weight  of  an  acknowledged  necessity. 

Schoolhouses  which  are  models  of  sanitary  clean- 
ness will  cause  a  demand  for  streets  and  public 
conveyances  of  like  character;  then  a//  public  build- 
ings will  be  brought  under  the  same  laws  of  evi- 
dent wisdom. 

Not  till  the  right  of  cleanness  is  added  to  the 
right  to  be  well  fed,  and  both  are  assured  to  each 
individual  by  the  knowledge  and  consent  of  the 
whole  people,  can  the  greater  gospel  of  prevention 
make  good  its  claims. 


CHAPTER   V. 
Chemicals  and  Their  Use  in  the  Household. 

EVERY  woman,  whether  she  knows  it  or  not,  ExpTrimLts 
is    every   day   performing   simple   experi-  in  the  Home, 
ments  in  chemistry.    Every  match  that  is  lighted, 
every  use  of  soap  on  the  body,  the  clothes  or  the 
utensils,   depends    upon   chemical   laws    for   the 
reactions  which  take  place. 

There  is  no  process  of  cooking  or  cleaning 
that  does  not  rest  upon  a  foundation  of  chemical 
or  physical  law.  Therefore  every  house  is  a 
laboratory.  Each  is  presided  over  by  a  director 
of  greater  or  less  intelligence. 

When  intellectual  interest  and  manual  dex- 
terity unite,  "drudgery"  is  eliminated. 

There  may  be,  too,  at  all  times  an  attitude  of 
discovery.  Many  of  the  most  important  chem- 
ical processes  have  been  found  out,  it  is  said, 
accidentally. 

In  most  persons  an  experiment  awakens  in- 
terest. The  housewife  should  be  a  cautious 
experimenter. 

An  understanding  of  simple  chemical  reac- 
tions tends  also  to  economy  in  household 
management. 


146  THE   CHEMISTRY   OF 

The  thrifty  housewife  may  not  only  save  many 
dollars  by  restoring  tarnished  furniture  and 
stained  fabrics,  but  may  also  keep  her  belongings 
fresh  and  "as  good  as  new"  by  the  judicious  use 
of  a  few  chemical  substances  always  ready  at  her 
hand. 

It  is  essential,  however,  that  she  know  their 
properties  and  the  effect  they  are  likely  to  have 
on  the  materials  to  be  treated,  lest  more  harm 
than  good  result  from  their  use.  A  good  exam- 
ple is  the  instant  disappearance  of  all  red  iron- 
rust  stains  when  treated  with  a  drop  of  hydro- 
chloric acid.  If,  however,  the  acid  is  not  com- 
pletely washed  out,  the  fabric  will  become  eaten, 
and  holes  will  appear,  which,  in  the  housekeeper's 
eye,  are  worse  than  the  stains.  This  danger  may 
be  entirely  removed  by  adding  ammonia  to  the 
final  rinsing  water,  which  neutralizes  any  remain- 
ing acid,  and  the  stained  tray-cloth  or  sheet  is 
perfectly  whitened. 

It  is  well  that  the  household  laboratory  should 
be  supplied  with  the  following  substances.  Not 
all  of  these  are  strictly  chemicals,  but  they  are 
included  by  courtesy,  as  it  were,  because  so 
closely  connected  with  the  chemical  reactions. 
Many  of  them  act  only  mechanically. 
Alkalies.  I.     Alkalies — substances  with  a  soapy  feeling 

and  which  turn  red  litmus  blue.     In  solutions 


COOKING  AND   CLEANING.  147 

they  neutralize  the  effects  of  acids.  When  the 
neutralization  is  complete  the  solution  is  said  to 
be  neutral,  and  it  will  not  change  the  color  of 
litmus.  This  neutral  substance  is  a  chemical 
salt. 

Alkalies,  except  ammonia,  injure  wool  fibres, 
hardening,  roughening  and  shrinking  them, 
while  the  caustic  alkalies  dissolve  them.  Only 
weak  alkalies  should  be  used  on  linen  or  silk. 

I.      Potassium    hydroxide,    KOH,    caustic    pot-    Caustic  Potash. 

ash.  This  can  be  bought  in  solid  form  to  use  in 
drains  for  removing  grease.  It  forms  a  soap, 
which  must  be  washed  out  of  the  pipes  by  thor- 
ough flushing.  It  is  one  of  the  strongest  alkalies 
and  must  be  used  with  caution.  It  is  dissolved 
in  water  with  the  evolution  of  great  heat,  caus- 
ing rapid  boiling.  Spatters  from  it  on  fabrics 
are  liable  to  burn  holes,  on  wood  will  darken  the 
color,  and  on  the  flesh  may  cause  deep  burns. 
'When  got  upon  the  flesh  or  upon  fabrics  it 
should  be  quickly  washed  off  and,  if  necessary, 
treated  with  vinegar.  It  is  usually  bought  in 
cans  as  ''concentrated  lye."*  It  combines  with 
fat  to  make  soft  soap. 

Potassium  is  a  common  ingredient  of  inland 
vegetation.  Caustic  potash  is  derived  from  wood 
ashes.     By  adding  water  to  wood  ashes,  potash 

*Today,  however,  this  is  more  often  caustic  soda  ih?in potash. 


148  THE   CHEMISTRY   OF 

(carbonate  of  potash)  is  dissolved  and  the  result- 
ing liquid,  lye,  may  be  used  for  purposes  of 
cleansing. 

Many  a  country  housewife  "sweetens"  the 
tainted  pork  barrel,  the  butter  firkin  or  pie  plate 
by  soaking  or  boiling  it  with  wood  ashes.  Ran- 
cid fats  are  acid.  This  acidity  can  be  neutral- 
ized by  the  alkali. 

Potash  is  often  used  to  soften  paint,  shellac 
and  other  woodwork  finishes,  to  facilitate  their 
removal  before  refinishing.  This  has  the  disad- 
vantage that  the  wood  is  darkened  by  the  alkali 
and  the  grain  is  raised. 
Caustic  Soda.  2.     Sodium  hydroxidc,   NaOH,  caustic  soda. 

This  compound  resembles  caustic  potash,  is  ef- 
fective in  slightly  less  degree  for  the  same  pur- 
poses; and,  being  cheaper,  is  much  more  exten- 
sively used.  The  element  sodium  is  common  in 
all  marine  and  seashore  plants,  and  is  the  metal 
in  common  salt,  from  which  it  is  now  prepared. 
Soda  Ash.  3.     Sodium     Carbonate,      NagCOg,     soda-ash 

(originally  from  the  ashes  of  seaweed).  When  a 
hot  solution  of  soda-ash  is  cooled,  a  crystalline 
form  is  left  known  as  sal-soda,  washing  soda, 
soda  crystals.  The  crystals  lose  water  when  ex- 
posed to  the  air  and  crumble  to  powder.  This 
powder  is,  therefore,  stronger  than  the  crystals. 

Sal-soda  is  used  most  commonly  in  softening 


COOKING  AND   CLEANING.  149 

hard  water,  for  keeping  the  plumbing  pipes  free 
from  grease  and  to  remove  grease  and  hardened 
food  from  cooking  utensils.  A  convenient  way 
to  prepare  sal-soda  for  general  use  is  to  put  one 
pound  of  the  ash  in  one  quart  of  water.  Let 
this  boil  until  the  soda  is  dissolved.  Bottle  when 
cold.  It  is  the  second  strongest  alkaline  cleaner, 
cheaper  and  more  safely  used  than  potash. 

4.  Sodium    bicarbonate,    NaHCOg,    cooking  Cooking  Soda 
soda,  carbonated  soda-ash.    In  cooking  it  is  used 

to  neutralize  acids,  to  aerate  dough  and  to  pro- 
duce effervescence  in  acid  solutions  by  liberating 
carbon  dioxide.  This  is  the  saleratus  of  today. 
The  true  saleratus  or  "pearlash"  used  seventy- 
five  years  ago  was  the  corresponding  potassium  ' 
salt,  KHCO3.  This  was  often  obtained  by  burn- 
ing corncobs,  mixing  the  ashes  with  water  and 
allowing  the  solution  to  evaporate  to  dryness.* 
In  cleaning,  sodium  bicarbonate  gives  a  mildly 
alkaline  action  when  dissolved  in  water.  With 
kerosene  it  is  nearly  insoluble  and  therefore 
gives  a  soft  friction.  Used  in  this  way  it  is 
effective  in  scouring  plumbing  fixtures,  where 
the  insoluble  whiting  might  clog  the  pipes.  For 
cleaning  purposes,  the  choice  between  borax  and 
bicarbonate  would  be  one  of  their  relative  cost. 

5.  Borax,  NajB^O^.    A  weakly  alkaline  sub-   Borax, 
stance,    most    useful    with    hard    water,    as    a 

*Now  "  Pearl  Ash  "  is  a  trade  name  for  KgCOg. 


160  THE   CHEMISTRY   OF 

bleacher  and  as  an  antiseptic.     It  is  much  more 
expensive  than  sal-soda,  but  is  less  liabl|g^ injure 
fabrics  and  to  irritate  the  skin.     It^Rtion  on 
colors  is  less  than  that  of  ammonia. 
Ammonia.  6.     Ammonia.     The  gas  NH3  is  dissolved  in 

water  in  varying  proportions,  forming  ammo- 
nium hydroxide,  or  aqua  ammonia,  NH^OH.  It 
is  the  only  volatile  alkali.  It  is  a  useful  sub- 
stance in  nearly  all  cleaning  processes,  and  to 
neutralize  acids. 

"Household  ammonia"  is  subject  to  impurities 
due  to  processes  of  manufacture.  These  often 
fade  colors  or  cause  white  materials  to  turn  yel- 
low. It  is  safer  and  cheaper  to  buy  the  concen- 
trated ammonia  from  a  druggist  or  a  dealer  in 
chemicals  and  add  the  water  at  home.  This  con- 
centrated ammonia  may  be  diluted  one-half  to 
one-sixth  and  yet  be  sufficiently  strong  for  most 
uses. 

It  loses  strength  rapidly  when  open  to  the  air, 
therefore  it  should  be  bought  in  quantities  pro- 
portioned to  its  use,  diluted  one-half  or  more 
and  kept  carefully  corked.  A  glass  stopper  is 
best,  altnough  rubber  will  serve.  Cork  is  acted 
upon  by  the  fumes  and  will  color  the  ammonia. 
If  the  glass  stopper  tends  to  stick,  it  may  be  kept 
slightly  smeared  with  vaseline. 

Ammonia    should    not    be    used    on    brass   or 


# 


#  • 


COOKING  AND   CLEANING.  151 


copper,  as  it  eats  them  rapidly.  It  discolors 
aluminum ;  but  the  resultant  compound  is  not 
injurious. 

7.  Soaps.     Hard  soap  is  sold  in  small  cakes,  ^°*p^" 
shavings  or  powder;  soft  soap   in  semi-liquid, 

or  liquid  soap  solutions.  There  are  many  grades 
from  those  that  are  neutral,  like  the  best  toilet 
soaps,  to  those  that  have  much  free  alkali.  The 
free  alkali  hastens  the  action,  but  is  injurious  to 
the  skin  and  to  many  other  materials.  Soap  and 
water  has  a  greater  solvent  power  than  water 
alone. 

8.  Ox-gall,  the  liquid  contents  of  the  gall-  Ox-Gail 
bladder  of  beef  creatures,  is  a  natural  soap.     It 

is  excellent  for  cleaning  colored  fabrics.  It  may 
be  used  clear  or  with  tepid  water.  It  decomposes 
readily  and,  therefore,  must  be  used  while  fresh. 

II.  Acids  —  substances  with  a  sour  taste  and  ^dds. 
which  change  blue  litmus  red.  An  acid  will  also 
liberate  carbon  dioxide  from  cooking  or  washing 
soda.  In  general,  weak  acids  lighten  the  color 
of  wood,  while  strong  acids  burn  it.  Acids  act 
injuriously  on  all  metals  if  allowed  to  remain  in 
contact  with  them.  The  metallic  salts  that  are 
formed  are  often  very  poisonous. 

When  used  with  caution  acids  are  effectual  in 
removing  iron  and  fruit  stains.  They  remove 
color  from  some  fabrics. 


152 


THE   CHEMISTRY   OF 


Acetic  Acid. 


Lactic  and 
Citric  Acids. 


Dilute,  cold,  acid  solutions  do  not  readily  in- 
jure cotton  or  linen,  while  hot,  strong  solutions 
injure  the  fibre.  No  acid  should  be  allowed  to 
dry  upon  cloth. 

I.  Acetic  acid,  H(C2H302),  is  the  acid  of  vin- 
egar and  for  many  purposes  it  may  be  used  in  this 
form.  For  delicate  processes,  however,  the  other 
substances  present  may  stain  or  interfere  with 
the  action,  so  that  the  pure  acetic  acid,  much 
diluted,  is  better.  It  is  volatile,  therefore  any 
excess  is  not  likely  to  injure  the  fabric  by  con- 
centration in  it  on  drying,  as  will  hydrochloric 
and  oxalic  acids.  While  acids  clean  copper  and 
brass  quickly  by  combining  with  the  tarnishing 
salts,  thus  exposing  a  fresh  surface,  this  new 
surface  soon  tarnishes  again,  and  the  process 
must  be  repeated.  If  any  acid  remains,  as  it  is 
likely  to  do  in  seams  and  grooves,  metallic  salts 
will  be  formed.  Copper  acetate,  which  is  formed 
when  brass  or  copper  is  treated  with  vinegar,  is 
very  dangerous. 

Sour  milk  contains  lactic  acid;  lemons,  citric 
acid,  and  this  is  perhaps  the  best  natural  acid  to 
use  for  cleaning  purposes.  It  should  be  used 
with  caution,  however,  as  it  is  strong  enough  to 
affect  some  colors  and  reacts  with  metals,  as 
copper,  brass  and  iron.  Rhubarb,  tomatoes,  sor- 
rel, etc.,  contain  acid  principles.     They  can  be 


COOKING  AND    CLEANING.  153 

used  in  emergencies  and  are  less  liable  to  "eat" 
fabrics. 

2.  Oxalic  acid,  Hg  (  CgO^ ) ,  is  found  naturally  in   Oxaik  Add. 
some  plants,  as  oxalis  and  sorrel.     It  is  bought 

in  crystals,  which  are  quickly  soluble  in  hot  and 
more  slowly  in  cold  water.  It  is  very  useful  in 
removing  stains  from  white  fabrics  and  may  be 
used  on  some  colors  (any  acid  to  be  used  on 
colored  fabrics  should  be  tested  first  on  a  piece 
of  the  goods  or  on  some  hidden  part,  as  a  seam). 
Hot  solutions  of  oxalic  acid  are  more  effective 
than  cold.  When  very  strong  it  makes  the  finger 
nails  brittle  and  may  irritate  the  skin  tempo- 
rarily. It  must  be  labeled  "Poison,"  and  should 
be  kept  out  of  the  reach  of  children. 

Note.  —  The  strong  acids  destroy  the  coats  of  the  stomach  and  there- 
fore are  poisonous  in  a  general  sense,  although  not  in  the  strict  sense  in 
which  strychnine  is. 

3.  Tartaric  acid,   'H.2(Cill^OQ) ,   the  acid  of   Tartaric  Adds, 
cream  of  tartar  is  one  of  the  safest  acid  agents. 

The  Rochelle  salt  of  Seidlitz  powders  is  a  sodium 
potassium  tartrate.  In  "  soda  powders  "  one  paper 
contains  tartaric  acid,  the  other  sodium  bicar- 
bonate. 

The  crude  tartar  or  argol  is  formed  as  a  hard 
crust  or  deposit  on  the  bottom  and  sides  of 
vessels  in  which  wine  is  manufactured. 

4.  Hydrochloric  or  muriatic  acid,  HCl,  most  acV^ 


154 


THE   CHEMISTRY   OF 


valuable  for  removing  iron  stains  from  fabrics 
and  other  materials.  It  sometimes  injures  silk 
and  must  be  used  with  caution  on  colored  goods. 
A  twenty  per  cent  solution  is  effective,  but  it  will 
lose  its  strength  unless  very  tightly  corked  with 
glass  or  rubber.  The  fumes  escaping  around  the 
stopper  will  rust  metals  and  "eat"  fabrics  even 
at  some  distance. 

Whenever  this  acid  is  used  there  should  be 
thorough  rinsing  of  the  fabric  in  water,  prefer- 
ably warm,  and  then  neutralization  in  ammonia. 

Bleachers.  jn,     Blcachcrs.     Thcsc   are   sometimes   used 

to  remove  color  from  colored  fabrics,  but  more 
often  to  remove  the  yellow  or  brownish  discol- 
oration from  fabrics  which  are  naturally  yellow 
or  which  were  originally  white. 

Sometimes  the  action  is  the  result  of  adding 
oxygen  to  the  coloring  matter;  sometimes  it 
takes  oxygen  away.  In  both  cases  colorless  com- 
pounds are  left,  and  in  both  cases  moisture  is 
necessary. 

Sunshine.  The  bcst  blcachcr  is  sunshine  with  moisture. 

The  action  here  is  very  complex,  resulting  in  the 
formation  of  ozone,  but  there  is  never  any  harm 
to  the  fabric.  The  best  way  of  using  "Nature's 
bleach"  is  to  spread  the  fabrics  on  the  grass,  wet 
them  frequently  with  soapy,  or  better  with  borax 
or  ammonia  water,  leave  out  over  night  for  the 


COOKING  AND   CLEANING.  155 

dew  to  form  on  them,  turn  occasionally  that  all 
parts  may  be  acted  upon,  and  continue  this  until 
the  desired  whiteness  is  reached. 

In  ''dog  days,"  however,  the  fabrics  must  be 
carefully  watched,  else  they  will  mildew. 

The  best  time  for  grass  bleaching  is  during  the 
long  days  of  June. 

If  grass  is  not  available,  any  other  means  by 
which  the  wet  cloth  can  be  exposed  to  direct  sun- 
shine will  answer.  The  wet,  yellow  handkerchief 
or  lace  may  be  kept  by  the  sunny  window  until 
bleached. 

Cloth  laid  on  the  snow  bleaches  fairly  well. 
When  clothes  freeze  the  moisture  is  retained  so 
much  longer  that  even  in  the  short,  sunny  days 
of  winter  considerable  bleaching  may  be  done. 

All  bleaching  with  chemicals  is  attended  with 
danger  to  the  fibre ;  but  it  is  so  much  more  rapid 
and  so  convenient  a  method  that  not  only  its 
dangers  should  be  understood,  but  also  how  to 
obviate  them. 

When  the  chemical  has  completed  its  action 
with  the  coloring  matter,  it  attacks  the  fibre 
unless  quickly  removed. 

I.     Hydrogen   peroxide,   HgO,,   may  be  pur-  Hydrogen 
chased  as  a  five  per  cent  liquid.    This  is  a  power- 
ful oxidizing  agent.     It  loses  the  extra  atom  of 
oxygen  readily  and  should  be  kept  in  a  dark  place, 
preferably  closed  with  a  rubber  stopper. 


156 


THE   CHEMISTRY   OF 


Sulphur 
Dioxide. 


Chloride  of 
Lime. 


It  may  be  safely  used  with  all  fibres,  being 
especially  good  for  wool.  The  bleaching  action 
is  permanent. 

It  is  an  excellent  disinfectant  for  wounds,  sore 
throat,  etc. 

2.  Sulphur  dioxide,  SOg,  is  made  by  burning 
sulphur  in  the  air.  With  moisture  the  dioxide 
forms  sulphurous  acid,  H2SO3. 

This  is  effective  on  moist  silk,  wool,  straw  and 
paper.  The  fumes  should  not  be  breathed.  The 
country  housewife  attaches  the  wet,  yellowed 
straw  hat  to  the  bottom  of  a  barrel,  which  is 
then  inverted  over  a  kettle  of  coals  and  sulphur. 

This  is  much  less  destructive  to  the  fibre  than 
chloride  of  lime,  but  the  color  often  returns. 
The  fumes  from  a  burning  match  held  under 
the  wet  hand  will  remove  the  purple  stains  left 
from  black  kid  gloves.  They  are  also  very  effect- 
ive for  blueberry  and  blackberry  stains. 

The  common  sulphur  candle  is  a  convenient 
means  of  obtaining  sulphur  fumes.  They  may 
be  readily  concentrated  by  inverting  over  the 
candle  a  paper,  cardboard  or  other  funnel. 

3.  Chloride  of  lime  is  also  called  bleaching 
powder.  Its  composition  is  not  definitely  known, 
but  approximately  is  CaOCU.  When  dissolved  in 
water  it  shows  the  presence  of  both  calcium 
hypochlorite    and   calcium    chloride.     A   similar 


COOKING  AND  CLEANING.  157 

compound  is  sometimes  called  "  chlorinated  lime." 
(  Chlorinated  soda  is  also  on  the  market. ) 

When  treated  with  acids  this  gives  off  chlorine, 
freely.  The  carbon  dioxide  in  the  air  liberates 
it  slowly,  so  that  its  very  presence  in  the  house 
(or  its  use  as  a  deodorizer  or  disinfectant)  is  a 
prolific  source  of  rust  and  deterioration  of  cotton 
and  other  fabrics. 

Whether  used  for  general  bleaching  or  in  the 
removal  of  stains,  thorough  rinsing  and  neutral- 
ization in  ammonia  water  must  follow,  else  the 
fabric  will  suffer. 

4.  Javelle  water,  really  sodium  hypochlorite,   javeiie  water. 
is   a  compound  made  by   mixing   "chloride   of 

lime"  and  sodium  carbonate.  It  is  excellent 
for  the  treatment  of  old  or  obstinate  stains  as 
well  as  a  general  bleach.  Sodium  hyposulphite 
(see  below)  or  thorough  rinsing  and  ammonia 
water  should  be  used  afterward. 

5.  Sodium  thiosulphite — called  also  hyposul-   Hyposulphite, 
phite,  NagSaOg  +  5H2O,  the  "hypo"  of  the  pho- 
tographer— is  effective  in  removing  the  marks 

of  indelible  ink  containing  silver  nitrate. 

6.  Borax  (see  page  149).  Borax. 
IV.    Solvents.    For  grease  there  are  naphtha,  Solvents. 

benzene,  gasoline,  ether,  chloroform,  extremely 
volatile;  kerosene,  turpentine,  carbon  tetrachlo- 
ride, coal  tar  benzene  or  benzole  CqHq,  alcohol  less 
volatile. 


158  THE   CHEMISTRY   OF 

The  vapors  of  all  these  substances  are  heav- 
ier than  air,  therefore  sink.  They  should  be  used 
out-of-doors  or  by  an  open  window,  and  never 
where  there  is  any  fire.  There  should  be  a  cur- 
rent of  air  near  the  floor  to  ensure  quick  removal 
of  the  vapor. 

Turpentine  is  a  resinous  oil  which  serves  as  a 
solvent  for  paint,  grease,  tar  and  wax.  Mixed 
with  oil,  preferably  boiled  linseed,  it  makes  the 
best  general  furniture  polish.  It  cleans  more 
readily  than  kerosene,  but  does  not  give  so  good 
a  polish.  It  removes  ink  stains  from  polished 
woods,  from  which  it  usually  removes  the  gloss 
and  should  be  followed  by  oil  and  hard  rubbing. 
It  will  remove  some  inks  from  colored  fabrics. 
In  the  laundry  it  tends  to  whiten  clothes.  When 
fresh  it  is  clear  and  has  little  odor.  When  ex- 
posed to  the  air  it  takes  up  oxygen,  darkens  and 
thickens.  This  should  not  be  used  on  fabrics,  as 
it  will  itself  stain. 

The  vapors  of  chloroform  and  carbon  tetra- 
chloride are  non-inflammable  and  non-explo- 
sive. These,  like  ether,  should  be  used  where 
there  is  a  good  draft,  as  they  produce  anaesthesia. 
Chloroform  is  least  likely  to  injure  colors, 
although  ether  is  usually  safe. 
Oiia.  V.     Oils.     The  most  common  vegetable  oils 

are  raw  and  boiled  linseed,  sweet  or  olive  and 


COOKING  AND   CLEANING.  159 

cottonseed.  They  are  all  good  for  polishing 
woodwork  and  metals,  for  softening  and  bright- 
ening leather  (particularly  olive  oil),  to  imbed 
frictional  materials,  as  emery  for  iron,  rotten- 
stone  or  tripoli  for  brass  and  copper;  to  soften 
pitch,  tar,  etc. 

Mineral  oils  are  kerosene,  an  excellent  cleaner, 
a  good  polisher,  a  solvent  of  vaseline,  an  insecti- 
cide; and  paraffin  oil — less  odorous  than  kero- 
sene but  a  little  more  expensive.  Mixed  with 
turpentine  in  equal  parts  it  makes  an  excellent 
furniture  polish  for  very  light-colored  woods 
when  the  linseed  oil,  which  is  usually  used,  might 
darken  them  too  much;  coal  tar  benzine,  CsHg, 
is  excellent  for  removing  grease,  pitch  and  resin. 

VI.  "Alcohols."      Ethyl    alcohol,    C2H5OH,  AkohoU. 
"grain  alcohol,"  is  valuable  for  removing  stains. 
"Wood  alcohol,"  CH3OH,  is  less  effective  and  is 
poisonous    when    taken    internally.      It    should 
therefore  be  labeled  "Poison." 

Denatured  alcohol  may  or  -may  not  be  effective 
for  use  on  fabrics,  according  to  the  foreign 
substances  which  have  been  added. 

Alcohol  dissolves  shellac  and  turns  varnish 
and  wax  white.  White  stains  on  shellaced  wood 
are  removed  by  gentle  tapping  with  a  bit  of 
flannel  cloth  wet  in  alcohol. 

VII.  Stiffening  Agents.     Starch  is  obtained  stiffening 


160  THE   CHEMISTRY   OF 

from  many  plants,  but  chiefly  for  laundry  uses 
from  corn,  wheat  and  rice.  Potatoes  and  sago 
also  furnish  it.  Wheat  starch  is  most  satisfac- 
tory for  general  purposes.  It  gives  a  more  flex- 
ible stiffness  and  smoother  surface  than  corn 
starch. 
Starch.  Rice  starch  is  excellent  for  delicate  work,  as 

fine  dress  goods  and  laces.  As  was  shown  in  the 
previous  pages,  uncooked  starch  is  not  soluble  in 
water. 

In  cold  starching  the  spaces  between  the 
threads  of  the  fabrics  are  filled  and  the  surface 
coated  with  the  fine  powder.  The  heat  of  the 
iron  with  the  moisture  brings  about  the  change 
of  condition  and  great  stiffness  results. 

It  is  better  for  general  stiffening  purposes  to 
cook  starch  thoroughly  before  applying  it  to 
the  fabric.  As  this  cooking  may  caramelize  a 
part,  making  it  slightly  yellow,  a  very  little  blu- 
ing may  be  added  to  counteract  it.  Thoroughly 
cooked  starch  should  not  stick  to  a  hot  iron ;  but 
a  little  turpentine,  wax  or  paraffin  added  helps 
the  iron  to  slip  over  the  surface  more  readily 
and  adds  some  gloss. 

A  little  borax  in  the  starch  preserves  the  stiff- 
ness of  starched  articles  when  they  are  exposed 
to  dampness,  as  at  the  seashore. 

Starched  articles  should  not  freeze  before 
ironing. 


COOKING  AND   CLEANING.  161 

Prepared  starches  are  sometimes  made  soluble 
by  treatment  with  acids.  These  frequently  affect 
the  color  of  colored  fabrics  upon  which  they  are 
used. 

Some  also  have  borax  or  other  alkali  combined 
with  them,  and  these  also  change  colored  fabrics. 

Blues,  pinks  and  greens  seem  to  be  most  sus- 
ceptible to  these  changes.  If  a  blue  is  turned 
pinkish  it  may  be  well  to  add  a  little  ammonia  or 
borax  to  the  starch;  if  pink  is  turned  blue,  add 
a  little  acid — clear  vinegar  or  lemon  juice.  Per- 
haps the  safer  way  is  better,  i.  e.,  to  use  only  the 
starch  bought  in  bulk. 

Gum  arable,  sugar,  glue  and  gelatine  are  all  other  Agenti 
valuable  for  stiffening  thin,  delicate  fabrics. 

Black  laces,  straw  hats  and  ribbons  are  often 
stiffened  sufficiently  by  rinsing  them  in  alcohol 
and  water.  This  slightly  dissolves  the  still 
remaining  stiffening. 

VIII.  Bluings.  These  substances  are  used  to  Bluings, 
counteract  or  cover  by  their  blue  color  the  yel- 
lowness which  results  from  imperfect  washing  or 
rinsing;  from  too  much  or  too  strong  alkali; 
from  iron  in  the  water ;  or  from  the  action  of  the 
air  or  the  absence  of  light,  as  when  fabrics  are 
unused  and  stored  in  dark  places.  Blue  and 
■yellow,  however,  do  not  make  white.  The  color 
which  results  from  the  use  of  bluing  varies  from 
gray  to  green  or  blue  when  compared  with  white. 


162  THE   CHEMISTRY  OF 

The  bluings  act  either  mechanically  by  leaving 
a  fine,  impalpable  powder  among  the  meshes  as 
ultramarine,  or  by  a  tint  absorbed  by  the  fibre 
from  the  blue  solution. 

The  public  laundries  use  almost  exclusively  an 
aniline  blue.  This  may  be  purchased  solid  or 
liquid  and  is  a  real  dye.  It  requires  an  acid 
medium  before  it  will  set,  and  too  many  times 
this  acid  injures  the  fabrics.  As  it  is  a  dye,  it  is 
difficult  to  remove  the  effects  when  too  much  is 
used. 

A  good  blued  water  is  excellent  for  preserving 
the  original  color  of  blue  fabrics.  It  also  im- 
proves the  appearance  of  dull  or  blue-black 
goods. 

Frictionai  IX.     Frictioual  Materials.     These  do  not  act 

chemically,  but  are  important  agents  in  the  proc- 
esses of  cleaning  and  preservation.  They  may 
be  combined  with  soap,  oils  or  other  substances 
into  solid  or  paste-like  form. 

The  best  of  the  frictionai  materials  are  whit- 
ing, silicon,  rouge,  rotten-stone,  tripoli,  emery, 
pumice  and  common  sand  of  various  degrees  of 
coarseness.  Coal  ashes,  sifted,  make  an  excellent 
frictionai  material. 

The  commercial,  prepared  forms  are  often 
more  convenient  for  use,  but  much  more  expen- 
sive;   and  any  undesirable,  sharp,  gritty  parti- 


Materials. 


COOKING  AND    CLEANING.  163 

cles,  which  would  scratch  or  mar  the  article 
scoured,  might  not  be  detected  until  the  injury 
occurred.  Again  the  temptation  is  strong  to  put 
into  these  manufactured  materials  substances 
which  will  "take  hold  quickly,"  or  "do  the  work 
in  half  the  time,"  and  these  are  apt  to  be  injuri- 
ous to  the  articles  cleaned. 

X.  Absorbent  Materials.     Pipe  clay,  Fuller's  ^^*t°j|^^* 
earth,  French  chalk,  are  perhaps  the  best.     It 
should  be  remembered  that  starch,  flour,  meal, 
sawdust,    blotting   paper   and   similar    materials 

have ,  much  absorbent  power.  These  extract 
liquids  mechanically  and  therefore  do  not  affect 
the  fabric. 

XI.  Miscellaneous:     i.     Alum,  a  crystalline  Alum. 
double  salt  of  potassium  and  aluminum.     It  is 
used  for  clearing  water  from  suspended  organic 
matter  by  coagulation,  for  "fixing"  colors  and 

for  making  cotton  fabrics  less  inflammable. 

For  the  laundry,  two  ounces  of  alum  to  a 
gallon  of  water  is  sufficient.  Less  than  this  will 
set  most  colors. 

Sugar  of  lead,  lead  acetate,  fixes  colors, 
but  it  is  a  strong  poison  and  its  use  is  not 
recommended. 

2.     Litmus   paper    is    convenient    for    testing  Litmus  Paper, 
solutions,  either  for  acidity  or  alkalinity.     The 
red  paper  will  give  a  rough  test  of  free  alkali  if 


164  THE   CHEMISTRY   OF 

it  be  moistened  and  laid  on  soap ;  the  blue  paper 
for  acid,  on  bread  dough,  etc. 

One  piece  may  be  used  alternately  in  acid  and 
alkaline  solutions  an  indefinite  number  of  times. 
Salt  3.     Sodium  chloride,   NaCl,  common   salt,   is 

used  as  a  condiment,  an  antiseptic;  for  friction 
and  absorption;  to  remove  silver  sulphide  (see 
p.  112)  ;  in  the  laundry  for  fixing  colors  tem- 
porarily and  to  aid  in  removing  red  wine,  blood 
and  iron-rust  stains. 

Its  action  in  setting  colors  is  chiefly  in  decreas- 
ing the  solvent  power  of  the  water. 

New  goods,  liable  to  fade,  should  be  rinsed  in 
it  before  being  washed  with  soap. 


CHAPTER   VI. 
Antiseptics,  Disinfectants,  Insecticides 

FUNDAMENTALLY  and  ordinarily  clean- 
ness depends  upon  the  prevention  or  re- 
moval of  unclean  conditions — both  the  presence 
of  the  living  agents  and  that  of  the  organic 
matter  on  which  they  feed.  Rosenau  says: 
"While  the  old  idea  that  filth  and  unsanitary 
conditions  breed  disease  de  novo  is  wrong,  it  is 
nevertheless  true  that  these  conditions  keep 
the  infectious  principles  alive  and  favor  their 
propagation." 

When  infectious  material  is  present,  danger 
is  imminent  and  safety  may  require  that  the 
living  agents  be  destroyed  that  they  be  not 
spread  about. 

If  their  growth  can  be  prevented,  a  measure  Antisepsis. 
of  safety  is  attained.  This  is  the  condition  of 
antisepsis.  It  is  brought  about  by  producing 
unfavorable  conditions  of  growth.  For  this  pur- 
pose positive  or  negative  means  may  be  em- 
ployed. The  addition  of  sugar  in  preserves 
lessens  the  air  and  water  supply  of  the  ferments ; 


Disinfection. 


166  THE   CHEMISTRY   OF 

salt  withdraws  moisture;  drying  by  any  means, 
as  the  admission  of  sunUght  and  fresh  air — 
these  are  all  antiseptic  measures.  Or,  substances 
may  be  applied  which  will  retard  or  prevent  the 
growth  of  the  germs.  These  are  called  antisep- 
tics; soap,  salt,  strong  acids,  essential  oils, 
smoke,  all  act  in  this  manner.  Weak  solutions 
of  substances  which  when  strong  will  kill  the 
germ  usually  prevent  or  retard  its  action.  Boric 
acid  is  one  of  the  best  of  the  chemical  antiseptics. 

But  this  is  only  partial  immunity.  Safety  re- 
quires that  the  living  agent  of  infection  be  killed. 
This  is  the  office  of  disinfection.  Substances 
which  kill  disease  germs  are  called  disinfectants. 
All  disinfectants  are  germicides.  Sterilization 
means  the  absence  of  all  life,  whether  by  proc- 
esses of  removal  or  death.  This  is  a  much 
broader  term  than  disinfection.  Disinfectants 
may  kill  the  pathogenic  forms,  while  many  harm- 
less ones  remain.  Sterilization  would  affect  all. 
This  is  seldom  necessary.  The  state  of  asepsis 
is  equivalent  to  sterilization. 

An  ideal  disinfectant  will  destroy  the  patho- 
genic germs  without  injury  to  the  infected  mate- 
rial. This  may  be  difficult  to  find,  as  no  one 
agent  is  applicable  either  to  all  germs  or  to  all 
materials.  Direct  sunshine  is  Nature's  best  and 
cheapest    disinfectant.      It   will,    however,    fade 


COOKING  AND   CLEANING.  167 

color;  but  this  should  not  be  considered  where 
infectious  material  is  liable  to  be  present.  It 
destroys  the  superficial  spores  as  well  as  the 
active  forms ;  but  cannot  penetrate  opaque  ob- 
jects, and  not  deeply  into  solutions.  It  is  most 
effective,  then,  on  surfaces. 

Dry  heat,  300°  F.,  is  sufficient  to  destroy  the  Dry  Heat, 
common  pathogenic  germs,  but  this  is  far  above 
what  can  be  used,  without  injury,  in  most  cases. 

Dry  heat  is  not  so  effective  as  moist  heat. 
Anything  that  can  be  boiled  or  steamed  can  be 
most  surely  made  safe. 

In  "Disinfection  and  Disinfectants,"  Dr.  Ros- 
enau  says,  regarding  dry  heat,  boiling  and 
steam : 

"Most  materials  will  bear  a  temperature  of 
110°  C.  (about  230°  F.)  without  much  injury, 
but  when  this  temperature  is  exceeded,  signs  of 
damage  soon  begin  to  show.  Scorching  occurs 
sooner  in  woolen  materials,  such  as  flannels  and 
blankets,  than  with  cotton  and  linen.  The  over- 
drying  renders  most  fabrics  very  brittle,  but  this 
injury  may  be  lessened  by  allowing  the  materials 
which  have  been  subjected  to  dry  heat  to  remain 
in  the  air  long  enough  to  regain  their  natural 
degree  of  moisture  before  manipulating  them. 

"The  ordinary  household  cooking  oven  is  as 
good  as  any  specially  contrived  apparatus  for  the 
disinfection  of  small  objects  by  dry  heat.  In  the 
absence  of  a  thermometer  it   is   usual  to  heat 


168  THE   CHEMISTRY   OF 

the  oven  to  a  point  slightly  below  the  tempera- 
ture necessary  to  brown  cotton,  and  expose  the 
objects  no  less  than  one  hour. 

"Dry  heat  fixes  many  stains,  so  that  they  will 
not  wash  out.  This  is  especially  marked  with 
albuminous  materials  coagulable  by  heat,  and 
the  method  should  not  be  used  for  the  disinfec- 
tion of  fabrics  and  objects  soiled  with  blood, 
sputum,  excreta  or  similar  substances." 

The  objection  to  such  use  of  the  oven  lies  in 
the  handling  of  infected  articles  in  the  kitchen, 
the  worst  place  in  the  house  to  set  free  these 
dangerous  plants. 

Steam.  "Steam  is  the  most  valuable  disinfecting  agent 

we  possess.  It  is  reliable,  quick,  and  may  be 
depended  upon  to  penetrate  deeply"  if  the  appli- 
cation is  prolonged.  "It  does  more  than  disin- 
fect; it  sterilizes.  Bacteria  are  killed  instantly, 
spores  are  killed  in  a  few  minutes,  and  it  may 
therefore  be  used  to  destroy  the  infection  of  any 
one  of  the  communicable  diseases.  .  .  ." 

"Steam  is  very  apt  to  shrink  woolens  and  in- 
jure silk  fabrics.  It  ruins  leather,  fur,  skins  of 
all  kinds,  also  rubber  shoes,  mackintoshes  and 
similar  articles  made  of  impure  rubber." 

Boiling.  "Boiling   is    such   a   commonplace,    every-day 

process  that  it  is  often  neglected  in  practical  dis- 
infection, despite  the  fact  that  it  is  one  of  the 
readiest  and  most  effective  methods  of  destroy- 
ing infection  of  all  kinds.  An  exposure  to 
boiling  water  at  ioo°  C,  continued  half  an  hour, 
will    destroy    the    living    principles    of    all    the 


COOKING  AND   CLEANING.  169 

known  infectious  diseases,  even  very  resisting 
spores.  .  .  ." 

"Boiling  is  particularly  applicable  to  the  dis- 
infection of  bedding,  body  linen,  towels  and 
fabrics  of  many  kinds  ;  to  kitchen  and  tableware ; 
to  cuspidors,  urinals  and  a  great  variety  of  ob- 
jects. Surfaces,  such  as  floors,  walls,  beds,  fur- 
niture, etc.,  may  be  effectively  disinfected  by 
mechanically  cleansing  them  with  boiling  water. 
The  efficacy  of  boiling  water,  especially  when 
used  under  such  circumstances,  is  greatly  in- 
creased by  the  addition  of  corrosive  s^ublimate, 
carbolic  acid,  or  any  one  of  the  soluble  germi- 
cidal agents.  The  addition  of  lye,  borax  or  a 
strong  alkaline  soap  greatly  increases  the  pene- 
trating power  of  boiling  water,  when  applied  to 
surfaces  soiled  with  organic  or  oleaginous 
matters." 

"In  using  boiling  water  for  the  disinfection  of 
bright  steel  objects  or  cutting  instruments,  the 
addition  of  one  per  cent  of  an  alkaline  substance 
(bicarbonate  of  soda)  will  prevent  rusting  and 
injury  to  the  cutting  edge." 

"In  the  household,  small  objects,  body  and  bed 
linen,  and  other  fabrics  may  be  thoroughly  disin- 
fected by  streaming  steam  by  placing  a  large  pot 
or  washboiler  on  the  kitchen  fire,  and  arranging 
broom  handles  across  the  top  to  hold  the  mate- 
rials to  be  disinfected.  The  whole  should  be 
covered  with  a  sheet  or  cloth  to  retain  the  heat, 
and  steamed  for  an  hour  or  longer,  depending 
upon  the  degree  of  penetration  required  and  the 
energy  with  which  the  water  boils." 


170 


THE   CHEMISTRY   OF 


Fke. 


Solatioiis. 


Formalin. 


Here,  again,  excessive  precautions  must  be 
taken  in  handling  such  materials  in  the  kitchen. 

Fire  is  by  all  means  the  surest  disinfectant. 
Anything  which  can  be  burned  is  reduced  to  its 
inorganic  elements,  and  these  are  not  food  for 
the  pathogenic  germs. 

Whenever  any  infectious  material  is  liable  to 
be  produced,  as  in  all  discharges  from  commu- 
nicable diseases,  an  effort  should  be  made  to 
receive  it  in  or  upon  combustible  materials  of 
little  value  which  can  be  burned  immediately. 

Solutions.  These  must  not  only  be  strong 
enough,  but  in  such  quantity  that  the  strength 
shall  not  be  diluted  by  the  infectious  material 
beyond  the  effective  point.  The  time  of  action 
is  also  an  essential  factor.  If  the  microbes  are 
dry  it  will  take  a  certain  time  to  wet  them  before 
the  chemical  action  can  take  place.  Unless  the 
infected  material  can  be  immersed  in  the  disin- 
fectant solution,  it  is  difficult  to  keep  the  two  in 
contact  long  enough  to  effect  safety.  Tempera- 
ture, also,  is  an  important  factor  in  successful 
disinfection.  It  is  always  well  to  use  warm — 
hot,  if  possible — solutions  and  combine  their 
action  with  mechanical  removal,  or  scrubbing. 

Formalin  is  a  solution  of  formaldehyde.  A 
very  small  amount  is  antiseptic,  even  i  in  25,000 
or  50,000,  while  one  to  four  per  cent  kills  in  a 
short  time.    This  method  kills  spores,  also. 


COOKING  AND    CLEANING.  171 

Lime  or  quicklime,  CaO,  is  an  alkaline  earth. 
It  is  very  caustic  and  therefore  useful  in  destroy- 
ing organic  matter. 

Calcium   hydrate,   slaked   lime,    Ca(OH)2,    is  slaked  Lime, 
made  by  adding  one  part  of  water  to  two  parts 
of  quicklime. 

For  a  disinfectant,  freshly  slaked  lime  should 
be  used.  When  the  slaked  lime  is  exposed  to 
the  air  it  readily  takes  up  carbon  dioxide  and  is 
converted  into  calcium  carbonate,  which  has  no 
particular  disinfecting  power. 

Whitewash  is  slaked  lime  mixed  with  water,  whitewash. 
It  is  an  excellent  disinfectant  for  surfaces,  and  is 
a  form  of  milk  of  lime,  which  is  slaked  lime 
with  about  four  times  its  volume  of  water.  Milk 
of  lime  must  be  prepared  from  freshly  slaked 
lime  and  should  be  thoroughly  stirred  to  prevent 
the  insoluble  hydrate  from  settling.  At  least 
two  hours'  contact  should  be  allowed  when  this 
is  used  for  disinfecting  excreta,  and  it  should  be 
thoroughly  incorporated.  Milk  of  lime  as  used 
for  the  disinfection  of  excreta  in  the  United 
States  Army  posts  is  made  from  one  part,  by 
weight,  of  freshly  slaked  lime  to  eight  parts  of 
water.  The  excreta  should  stand  in  this  at  least 
two  hours  before  disposal. 

Ferrous  sulphate,   green  vitriol,  as  copperas,  Copperas. 
FeSO^,  so  commonly  depended  upon  as  a  disin- 


172 


THE   CHEMISTRY   OF 


fectant,  has  been  found  to  be  practically  useless. 
It  is  a  fairly  good  deodorant. 
Carbolic  Acid.  CarboHc  Gcid,  CgHgOH,  phenol,  does  not  co- 
agulate albuminous  matter  so  readily  as  corro- 
sive sublimate.  It  cannot  be  depended  upon  to 
kill  spores,  but  is  fairly  good  for  the  vegetative 
stage.  In  the  strengths  necessary  for  disinfec- 
tion it  is  not  destructive  to  fabrics,  colors,  metals 
or  wood. 

It  should  be  used  in  a  1-20  solution.  If  much 
is  required  it  will  be  cheaper  to  buy  the  con- 
centrated, which  is  a  ninety-five  per  cent  solution, 
and  reduce  it  to  the  desired  strength.  Four 
ounces  of  this  strength  with  five  pints  of  boiling 
water  will  give  the  required  1-20  solution.  The 
strong  acid  is  very  corrosive  and  must  not  touch 
the  skin. 

Quoting  again  from  Dr.  Rosenau's  book,  we 
find  that  "in  general  practice  carbolic  acid  is 
used  in  from  three  to  five  per  cent  solutions,  and 
an  exposure  of  no  less  than  half  an  hour.  Cloth- 
ing and  fabrics  require  deep  penetration,  and  are 
usually  left  in  the  solution  one  hour." 
Cresois.  Cresols  are  a  class  of  substances  obtained  frorft 

coal  tar,  found  as  impurities  in  commercial  car- 
bolic acid  or  phenol. 

Their  value  is  variable.     Creolin  is  a  common 
X  and  cheap   member  of  this   class.      It  contains 


COOKING  AND    CLEANING.  173 

about  ten  per  cent  of  cresols  and  a  small  amount 
of  phenol  held  in  solution  by  soap.  It  is  at  least 
equal  to  and  usually  superior  to  the  phenol.  A 
one  per  cent  solution  is  effective  for  ordinary 
purposes. 

Potassium  permanganate,  KMn04,  the  cham-  Potassium 
aeleon  minerale,  as  it  was  called  by  the  early 
chemists,  is  a  powerful  oxidizing  agent  and  a 
strong  germicide  under  limited  conditions.  It  is 
readily  reduced  and  rendered  inert  by  organic 
matter. 

Swampy  water  may  be  purified  by  it  if  enough 
is  added  to  allow  the  faint  pink  color  to  remain 
when  the  brown  precipitate  which  has  enmeshed 
the  bacteria  is  settled  or  filtered  off. 

There  is  a  possible  danger  of  internal  irrita- 
tion when  this  chemical  is  used  continuously  in 
potable  waters. 

Mercuric  chloride,  HgCla,  corrosive  sublimate,  con-osWe 

...  T      <  -11       1        1  •  1     Sublimate^ 

is  a  potent  germicide.  It  kills  both  active  and 
spore  forms.  It  is  a  virulent  poison,  corrodes 
metals,  and  unless  used  with  salt  it  coagulates 
albuminous  matter.  For  disinfection  of  excreta, 
therefore,  salt  must  be  added.  It  dissolves  with 
some  difficulty  in  three  parts  of  boiling  water 
or  sixteen  parts  cold  water.  It  should,  there- 
fore, be  powdered  before  the  water  is  added, 
care  being  taken  not  to  inhale  the  dust.     The 


174  THE   CHEMISTRY   OF 

solution  is  colorless  and  odorless,  and  has  been 
mistaken  for  water  when  not  properly  labeled. 
/  The  commercial  tablets  contain  salt  and  are  often 

colored  blue.  The  solution  may  be  slightly  col- 
ored with  indigo,  or  any  of  the  aniline  dyes,  and 
this  should  be  done  always  as  a  precautionary 
measure. 

The  i-iooo  strength  is  sufficient  to  kill  non- 
spore-bearing  species  if  allowed  to  act  for  half 
an  hour.  For  spores  the  1-500  solution  and  an 
hour's  exposure  is  required. 

A  gaseous  disinfectant  is  ideal  if  it  can  be 
made  to  penetrate  thick  fabrics  when  they  are 
slightly  moist,  so  that  the  gas  may  be  absorbed 
and  brought  into  intimate  contact.  This  is  diffi- 
cult to  accomplish  for  the  housewife,  because 
the  gas  must  be  delivered  under  pressure. 
Fofmaidehyde.  At  present,  formaldehyde  seems  to  approach 
this  ideal  most  nearly.  It  is  non-poisonous,  does 
not  injure  fabrics,  metals  or  mineral  surfaces. 
In  disinfecting  with  formaldehyde,  temperature 
plays  an  important  part.  The  gas  is  not  effective 
under  50°  F.  and  increases  in  power  with  the 
higher  temperatures.  Moisture,  also,  is  neces- 
sary for  its  effectiveness.  A  basin  of  water,  kept 
boiling,  may  be  used  to  furnish  the  moisture. 
The  gas  does  not  penetrate  thick  masses  or  fab- 
rics readily,  unless  it  is  delivered  under  pressure, 


COOKING  AND    CLEANING.  175 

therefore  such  articles  should  be  spread  out  as 
thin  as  possible,  and  more  time  should  be  allowed 
than  for  ordinary  disinfection. 

When  the  disinfection  of  a  room  with  a  gas 
is  completed,  the  doors  and  windows  should  be 
opened  as  quickly  as  possible.  If  a  person  enters 
the  room  to  do  this,  he  should  cover  the  eyes, 
nose  and  mouth  with  a  moist  cloth  to  prevent 
the  irritation  caused  by  the  gas.  Ammonia 
sprinkled  about  the  room  will  neutralize  the  gas, 
but  forms  with  it  a  substance  having  a  very 
persistent  odor. 

Soaps   have    an    antiseptic    action,    and    it    is  Soaps. 
asserted  by  many  that  pure  white  castile  soap 
is  germicidal. 

According  to  Dr.  Rosenau:  "Medicated  soaps 
are  for  the  most  part  a  snare  and  a  delusion  so 
far  as  any  increased  germicidal  action  is  con- 
cerned; in  fact,  the  addition  of  carbolic  acid,  bi- 
chloride of  mercury,  and  other  substances  which 
have  the  property  of  combining  with  the  soap, 
seems  actually  to  diminish  the  disinfecting  value 
of  that  substance.  As  a  rule,  a  very  small  quan- 
tity of  the  disinfecting  substance  is  added  to  the 
soap,  and  when  it  is  called  to  mind  what  an  ex- 
ceedingly small  quantity  of  soap  is  necessary  for 
the  ordinary  washing  of  the  skin,  and  the  further 
dilution  of  this  small  amount  by  the  water  used. 


176  THE   CHEMISTRY  OF 

it  is  easy  to  understand  that  medicated  soaps,  as 
ordinarily  applied,  cannot  have  an  energetic 
disinfecting  action," 

The  value  of  soap  is  in  its  superficial  cleansing, 
the  removal  of  objectionable  matter. 
Deodorants.  Another  class  of  substances  which  are  often 

used,  and  sometimes  with  danger,  are  those 
which  destroy  odors.  These  are  substances 
which  combine  with  the  decomposing  matter, 
forming  new  and  odorless  compounds.  Charcoal 
is  such  a  substance. 

This  is  the  office  of  a  true  deodorant.  The 
name  is  sometimes  applied  to  other  substances 
which  produce  no  chemical  or  physical  changes, 
but  simply  cover  up  the  odor  given  off  by  the 
decaying  matter  by  one  stronger  or  more 
agreeable. 

Deodorants  simply  destroy  smells ;  disinfect- 
ants and  germicides  destroy  germs.  Most  disin- 
fectants are  at  the  same  time  deodorants. 

The  question  is  constantly  asked,  "What  disin- 
fectants can  I  use  that  are  common  and  cheap?" 

The  last  published  report  of  the  American 
Public  Health  Association  speaks  authoritatively 
upon  this  question,  and  from  this  the  following 
quotation  may  be  taken  as  a  summary  of  the 
present  status  of  the  subject: 
^^onvV.''"      "The  weight  of  opinion  seems  to  be  that  alco^ 


COOKING  AND   CLEANING.  177 

hoi  from  40-60%  is  quite  a  strong  germicide, 
but  that  lower  and  higher  percentages  are  much 
weaker  in  their  action.  Two  observers  class  it 
about  midway  between  sublimate  and  carbolic 
acid  in  strength. 

"Whether  it  acts  as  a  direct  poison  or  indi- 
rectly through  the  water  present  is  not  yet  estab- 
lished, but  the  weight  of  opinion  seems  to  be  that 
it  acts  directly." 

The  vapor  from  boiling  alcohol  solutions 
is  more  effective  as  a  disinfectant  than  the 
solutions. 

"There  are  a  few  common  disinfectants  the 
efficiency  of  which  has  been  firmly  established, 
namely,  boiling  water,  hot  soda  solution  (about 
10%  solution  of  sal-soda  in  water),  milk  of  lime 
(pieces  of  lime  slacked  to  a  milk),  corrosive  sub- 
limate and  formaldehyde.  I  would  add  some  of 
the  cresol  preparations  except  that  they  are  pat- 
ented and  hence  not  cheap  enough  for  common 
use  in  the  United  States.  I  leave  out  carbolic 
acid  because  of  its  poisonous  properties,  and 
chloride  of  lime  because  of  its  uncertain  compo- 
sition. Nothing  better  or  more  effective  is 
needed  to  disinfect  feces  and  such  matters  than 
milk  of  lime ;  nothing  to  disinfect  clothes  than 
steam,  hot  water  or  hot  soda  solution ;  for  quick 
sterilization  of  the  hands  a  i-iooo  sublimate  solu- 
tion is  the  best ;  and  as  a  room  disinfectant, 
formaldehyde  properly  used  still  holds  the  first 
place.  .  .  ." 

Some  insects  are  known  to  carry  infectious  ^°*«<^' 


178  THE   CHEMISTRY   OP 

matter,  and  it  is  easy  to  understand  how  any 
animal  may  convey  such  material  from  one  place 
to  another  and  possibly  to  man.  They  certainly 
do  carry  on  their  bodies  minute  infectious  parti- 
cles gathered  from  moist  substances,  as  excreta, 
pus,  sputum,  over  which  they  have  crawled. 
They  carry  also  the  agents  of  decomposition 
from  decaying  food,  depositing  them  upon  other 
food  and  thus  starting  decomposition  in  it. 

In  some  cases  the  infectious  germ  is  intro- 
duced into  human  beings  from  the  body  of  the 
insect  as  it  stings  or  bites.  This  is  the  case  with 
the  flea  and  the  mosquito,  which  carry  malarial 
and  yellow  fever  germs. 

The  flies,  fleas,  ants,  etc.,  deposit  the  infectious 
material  on  the  skin  with  their  excrement,  and  in 
other  ways.  The  virulent  infection  is  rubbed 
into  the  little  wounds  or  scratched  into  the  skin 
as  a  result  of  the  irritation  caused  by  the  bites, 
thereby  setting  up  the  disease. 

Therefore  all  insects  may  be  looked  upon  with 
suspicion,  while  mosquitoes,  flies,  roaches,  bed- 
bugs and  fleas  should  receive  no  quarter  in  the 
clean  and  healthful  house. 
Insecticides.  Most  gcrmicidcs  are  insecticides.    Yet  formal- 

dehyde is  a  notable  exception.  It  has  slight 
effect  upon  insect  life. 

Sulphur  dioxide.     This  gas  holds  first  place 


COOKING  AND    CLEANING.  179 

for  killing  insects  and  vermin.  As  an  insecticide 
it  can  be  used  dry,  while  as  a  germicide,  as  has 
been  said,  moisture  is  necessary. 

Bisulphide  of  carbon,  CSg,  and  hydrocyanic 
acid  gas,  HCN,  are  both  powerful  insecticides. 
They  are  also  deadly  poisons  to  all  animal  life. 
They  should  therefore  never  be  used  except  by 
experts.  The  United  States  Government  has 
published  some  valuable  bulletins  upon  the  use 
of  these  substances. 

Kerosene  kills  bedbugs  and  their  eggs.  Ap- 
plied to  the  surface  of  water  at  the  rate  of  an 
ounce  to  fifteen  square  feet  of  surface  it  destroys 
mosquitoes  and  their  larvae.  It  is  therefore  use- 
ful in  covering  all  moist  matter  in  which  they 
may  breed. 

"Insect  powder,"  or  "  Persian  or  Dalmatian  in- 
sect powder,"  is  usually  the  powdered  flowers  of 
two  species  of  chrysanthemum,  C.  roseum  and 
C.  carneum.  They  are  also  sold  under  the  names 
of  pyrethrum  and  buhack.  The  powder  acts 
mostly  by  filling  the  breathing  holes,  causing 
suffocation.  It  will  kill,  but  too  often  only  stu- 
pefies the  insects,  which  should  then  be  gathered 
and  burned.  Water  bugs  and  fleas  are  driven 
from  their  lairs  to  be  caught  while  stupefied. 

The  powder  may  be  burned,  and  in  this  form 
is  quite  effectual  for  mosquitoes. 


180  THE  CHEMISTRY  OF 

The  poisonous  fly  papers  kill  the  insects,  but 
they  fall  everywhere  about  the  house,  and  the 
presence  of  these  arsenical  compounds  is  dan- 
gerous wherever  there  are  children. 

The  sticky  fly  papers  do  not  kill  but  hold  the 
insects,  and  they  die  from  exhaustion. 


BOOKS   OF  REFERENCE. 


Approved  Methods  for  Home  Laundering.     M.  B.  VaiL 

Art  and  Practice  of  Laundry  "Work.     M.  C.  Rankin. 

Bacteria,  Yeasts  and  Molds  in  the  Home.     H.  W.  Conn. 

Care  of  a  House.     T.  M.  Clark. 

Chemistry  of  the  Household.     M.  E.  Dodd. 

Chemistry  of  Plant  and  Animal  Life.     Harry  Snyder. 

Clean  Milk.     S.  D.  Belcher. 

Disinfection  and  Disinfectants.     M.  J.  Rosenau. 

Domestic   Economy  in  Theory   and   Practice.     Bidder  and 

Baddely. 
Drinking  Water  and  Ice  Supplies.     T.  M.  Prudden. 
Dust  and  Its  Dangers.     T.  M.  Prudden. 
Elementary  Laundry  Work.     Calder  and  Mann. 
Expert  Cleaner.     H.  J.  Seaman. 
Garment  Dyeing  and  Cleaning.     G.  H.  Hurst. 

Handbook  of  Domestic  Science  and  Household  Arts. 
L.  L.  W.  Wilson. 

Handbook  on  Sanitation.     G.  M.  Price. 

Home  Furnishing.     A.  M.  Kellogg. 

Home  Sanitation.     Richards  and  Talbot. 

House  and  Home.     M.  E.  Carter. 

House  that  Jill  Built.     E.  C.  Gardner. 

Household  Bacteriology.     S.  M.  Elliott. 

Household  Economics.     Helen  Campbell. 

Household  Hygiene.     S.  M.  Elliott. 

How  to  Drain  a  House.     G.  E.  Waring,  Jr. 

Hygiene  and  Public  Health.     L.  C.  Parkes. 


182  BOOKS  OF  REFERENCE. 

Laboratory  Notes   in    Household   Chemistry.      Vult^   and 

Goodell. 
Laundry  Manual.     Balderston  and  Limerick. 
Laundry  Work.     J.  L.  Sheppard. 
Outlines  of  Rural  Hygiene.     H.  B.  Bashore. 
Principles  of  Sanitary  Science  and  Public  Health.      W.  T. 

Sedgwick. 
Sanitary  and  Applied  Chemistry.     E.  H.  S.  Bailey. 
Sanitation  of  a  Country  House.     H.  B.  Bashore. 
School  Sanitation  and  Decoration.     Burrage  and  Bailey. 
Story  of  the  Bacteria.     T.  M.  Prudden. 
Story  of  Germ  Life.     H.  W.  Conn. 
Story  of  the  Living  Machine.     H.  W.  Conn. 
Text-Book  of  Physiological  Chemistry.     Hammersten. 
Text-Book  of  Physiology.     William  HowelL 


INDEX. 


Absorbents  of  grease,  100,  101, 163 

Acids,  41,  151 

Acetic,  o8, 152 

Butyric,  35 

Carbolic,  172 

Citric,  152 

for  iron  stains,  132 

Hydrochloric  or   Muriatic,  17,  41, 
132,  153 

Lactic,  152 

Oxalic,  116,  153 

Stearic,  43 

Tannic,  50 

Tartaric,  153 
Air,  as  food,  67 

not  the  agent  of  change,  73 

pollution  of,  84 

pure,  83 

a  substance,  85 
Albumin,  49 
Albuminoids,  50 
Alcohol,  30,  36,  159 
Alcohol,  as  solvent,  102, 110, 157 
Alkalies,  caustic,  89,  111,  146 

volatile,  89 
Alkali  metals,  88 
Alum,  163 
Aluminum,  117 
Ammonia,  89,  150 

uses  of,  73,  93, 102, 125, 139,  150 
Ammonium,  88,  89 
Animal  body,  a  living  machine,  47 

repair  of,  48 
Antisepsis,  165 
Art  of  cooking,  56,  62 
Atoms,  14 
Atomic  weight,  14,  16 

of  hydrogen,  14 

Bacteria,  36,  39,  74,  76,  77,  81 

action  of  in  disease,  80 

as  flavor  producers,  62 

food  of,  81 

spores  of,  75 
Bacteriology  of  bread-making,  36 
Baking  powder,  22,  23 


Beans,  52,  64 

Beer,  29 

Benzine,  98, 102, 157 

Biscuits,  39 

Bleachers,  154 

Bleaching,  134, 135 

Bleaching  powder,  135, 156 

Blinds,  82 

Blood  stains,  106, 129 

Blotting  paper  for  ink,  108 

Bluing,  133, 134,  161 

Boiling,  168 

Books  for  reference,  181 

Borax,  125, 128, 137, 139, 149 

Brass,  116 

Bread-making,  chemical  reactions  in, 

29,  30,  36 
Bread,  as  food,  33 

crust,  39 

fermented,  36 

flavor  in ,  39 

homemade,  37 

ideal,  34 

leavened, 35 

object  of  baking,  38 

reason  for  kneading,  37 

stale,  39 

temperature  of  baking,  37,  88,39, 54 
of  fermentation,  37 
Butter,  43 
Butyric  acid,  35 

Caesium,  88 

Calcium  hypochlorite,  128, 156 
Calories,  47 
Calorimeter,  19 
Cane  sugar,  28,29 
Carbohydrates.  26,  44,  63 
Carbolic  acid,  172 
Carbon  bisulphide  of,  179 
Carbon  dioxide  (carbonic  acid  gas), 
17,  18,19,25,30,36,37 
method  of  obtaining,  40 
Carbon  tetrachloride,  157 
Casein,  52 
Caustic  alkalies,  89,  147, 148 


184 


INDEX. 


Cayenne  pepper,  59 
Cellulose,  27 

Cheese  cloth  for  cleaning,  93 
Chemical  arithmetic,  17 
Chemical  change,  7 

produces  heat,  25 
Chemical  elements,  12,  16 
Chemical  equations,  17 
Chemical  experiments  in  the  home,  145 
Chemical  laws,  13, 14, 15 
Chemical  reactions,  17,  25 

in  bread  and  beer  making,  36 
Chemical  symbols,  16 
Chemicals  for  household  use,  145 
Chloride  of  lime,  126,  127,  128,  129, 

156, 177 
Chloroform,  102, 157, 158 
Cleaning  of  brass,  116 

fabrics,  97,  98 

glass,  96 

paint,  93 

powders,  113 

problems  of,  90 

processes  of,  88,  90 

silver.  111,  116 

wood,  90,  91, 92,  93 
Cleanness,  ideal  and  sanitary,  142 

personal,  143 

philosophy  of,  82,  85 

public,  144 

of  schoolhouses,  144 
Cocoa  and  coffee  stains,  127, 128 
Collagen,  50 

Colors,  setting  of,  140, 146 
Combining  weights,  14 
Combustion  of  food,  25,  26 

products  of,  84 
Compounds,  13 
Condiments,  56,  58,  59 
Consumption,  83 
Conversion  of  starch,  28,  30 
Cooking,  American,  58 

art  of,  56,  57,  62 

chemistry  of,  58 

discretion  in ,  62 

economy  in ,  60 

effect  of,  54 

fats,  46 

nitrogenous  food,  50, 63 

>bject  of,  53 

Starch,  32 

vegetables,  60 
Copper,  115, 116 
Copperas,  171 
Corrosive  sublimate,  173 
Cottonseed  oil,  43 


Cream  of  tartar,  23, 41, 42 
Creolin,  192 
Cresob,  192 

Decomposition,  64 

Definite  proportions,  law  of,  14 

Deodorants,  176 

Development  of  flavor,  56 

Dextrose,  29 

Diastase,  29 

Diet,  63,  65 

Diet,  fat  in,  45 

Dietaries,  68,  69 

Digestion,  28,  61,  63,  66 

of  fats,  44 

is  solution,  28 
Dirt,  definition  of,  78 

prevention  of,  98 
Disease,  cause  of,  80 

prevention  of,  79 
Dish  cloths  and  towels,  140 
Disinfectants,  166, 176 
Disinfection,  166 
Dry  heat,  167 
Dust,  71,  72,73,  75,  87,88 

in  air,  72,  76 

composed  of,  77 

on  fabrics,  97, 98 

germs,  80 

meteoric,  73 

spots,  103 

on  wood,  92 

Economy  in  cooking,  60 

of  mixed  diet,  65 
Effect  of  condiments,  58 

of  cooking,  54 
Eggs,  51 

Elements,  chemical,  12,  16 
Emery,  162 
Energy,  mechanical  unit  of,  47 

sources  of,  44 
Ether,  102,  157, 158 
Expansion  of  g^ases,  9 

of  water,  40 

Fabrics,  97,  98 
Fat,  digestion  of,  44 

in  diet,  44 

effect  of  high  temperature  on,  46 
Fats,  24,  43,  45,  55,  88 
Fermentation,  35,  39 
Finish  of  woods,  90 
Fire,  170 

Flavor,  46,  56,  57,  58,  60 
Flour,  use  of  >  in  bread,  39 


INDEX. 


186 


Food,  office  of,  24,69 
water  and  air  as,  68 
Formaldehyde,  174 
Formalin,  170 
French  chalk,  163 
Frictional  materials,  162 
Fruit  stains,  126, 127 
Fuel  in  body,  47 
Fuller's  earth,  163 
Fungi,  74 

Gases,  8 

Gasoline,  167 

Germs,  74,  80,  81 

Glass,  96 

Glucose,  29 

Gluten,  52 

Grass  stains,  129 

Grease,  87,  88,  100, 101, 102,  104,  135 

solvents  for,  91,  157 

on  wood,  1(^ 
Growth,    nitrogenous    food    required 

for.  48 
Gums,  24 

Hard  water,  119, 120 
Heat,  dry,  167 

produced  by  chemical  cnange,  24 

source  of  in  animals,  25 
Hydrochloric  acid,  41, 153 
Hydrogen,  14, 27, 44 
Hydrogen  peroxide,  155 
Hyposulphite,  157 

Ideal  bread,  34 
Indigo,  133 

Inflammable  substances,  98 
Ink  indelible,  109 

stains,  107, 108, 131 
Inoculation,  82 
Insect  powder,  179 
Insecticides,  178 

Iron  rust,  removal   of,  117,  131,  132, 
146 

Javelle  water,  126,  127, 128, 129, 130, 

157 
Jewelry,  115 

Kerosene,  91, 92, 96,  111,  116, 117, 181, 

141,  157, 179 
Kitchen  utensils,  117 

Lard,  43 
Laundry,  118-142 


Law  of  definite  proportions,  14 

multiple  proportions,  15 
Leather,  94 
Leaven,  35 
Leg^min,  52 
Lentils,  65 
Levulose,  29 
Lime,  slaked,  171 
Lithium,  88,  89 
Litmus  paper,  163 

Marble,  95, 109 
Matter,  changes  in,  5 

definition  of,  5 

forms  of,  8 
Medicine  stains,  127 
Mercuric  chloride,  173 
Metals,  95, 111,116 
Mildew,  130 
Milk  stains,  129 
Mixed  diet,  65 
Molds,  74,  77,  79 
Molecular  weight,  11 
Molecules,  14 
Mucous  stains,  129 
Multiple  proportions,  law  of;  15 
Muriatic  acid,  153 

Naphtha,  157 
Nature's  scavengers,  78 
Nickel,  117 
Nitrogen,  48 

Nitrogenous  food,  47, 49,  6S 
cooking  of,  50, 55 

Oils,  43,  45,  88,  92, 158 
Oil  finish,  91 
Oil  stains,  130 
Olive  oil,  44,  45 
Oxalic  acid,  147 
Ox-gall,  103,  151 
Oxygen,  15,  26,  43 
Oysters,  51 

Paint,  93, 104 
Paper,  94 
Pastry,  54 

Pathogenic  germs,  81 
Pearlash,149 
Pepsin,  64 
Peptones,  64 
Physical  change,  7 
Pipe  clay,  163 
Pitch,  105 

Plated  silverware,  112 
cyanide,  113 


186 


INDEX. 


Plumbing,  care  of,  141 

Porcelain,  96, 110 

Potash,  103, 122, 123, 147 

Potassium,  88 

Potassium  hydroxide,  147 

Potassium  permanganate,  173 

Preparation  for  food,  of  starch,  sugar 
and  fat,  24 

Prevention,  80,  98 

Products  of  decomposition,  64 

Proportion  of  nitrogenous  food  re- 
quired, 68 

Pumice,  95, 162 

Rations,  69 

Removal  of  dust,  spots  and  stains,  87 

Restoring  color,  97 

Rouge,  162 

Rotten-stone,  162 

Rubidium,  88 

Rust  of  iron,  117 

Saliva,  63 
Sal-soda,  148 
Salt,  17, 41,  42 
Saturation,  9 

Schoolhouse  sanitation,  143 
Seasonable  diet,  65 
Serving,  62 

Shellac,  dissolved  by  alcohol,  HI 
Silicon,  162 

Silver,  cleaning  of,  111,  113,  114, 115 
Silver  nitrate,  157 
Silver  polish,  113, 114 
Silverware,  112, 115 
Soap,  89,  120, 122, 124, 137,  139,  151, 
175 

bark,  121 

berry  tree,  121 
Soda,  42,  122, 124, 148, 149 
Soda  ash,  17, 123, 124,  148 
Sodium,  87 

Sodium  carbonate,  148 
Sodium  chloride,  17, 164 
Sodium  hydroxide,  148 
Sodium  thiosulphite,  157 
Soft  water,  119, 120 
Solution,  9,28,  50 
Solutions,  disinfecting,  170 
Solvents,  10,  78, 91, 101, 102, 106, 157 


Source  of  energy,  44 

Spores,  75 

Spots,  100,  118 

Stains,  100, 106, 118, 126, 127, 12f 

Starch,  24,  27,  28,  29,  30, 31,  160 

cooking  of,  32, 55, 61, 160 
Steam,  168 
Stearic  acid,  43 
Stiffening  agents,  159, 160 
Stimulants,  60 
Stoves,  care  of,  117 
Suet,  43 
Sugar,  24,  27, 29 

cane,  28 

fruit,  28 

of  lead,  163 

milk,  27,  28 
Sulphur  dioxide,  156, 178 
Sunlight,  82,  83,  84,  85, 154, 166 
Swellmg,  10 
Symbols,  16 
Syrups,  10 

Tables,  16, 23 

Tannin,  128 

Tarnish,  100, 101 

Tea  stains,  127, 128 

Temperature,  26,  46,  49,  52,  53 

Tripoli,  162 

Turpentine,  91, 102,  103, 126. 1S8 

Ultramarine,  133,  134,  162 
Utensils,  kitchen,  117 

Varnish,  91,  105 
Vegetables,  60 

Wall  paper,  94 

Washing  soda,  124, 125, 148 

Water,  118,  119,  120 

as  food,  67 

hard  and  soft,  119, 120 
Wax,  91, 105 
Whiting,  114,  162 
Wine  stains,  121 
Whitewash,  171 
Woodfinish,  90,  91,92 
Woolens,  washing  of,  139 

Yeast,  33,  35, 36,  37,  38,  74,  7» 


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